FUNGI PARASITIC UPON ALEYRODES GITRI 



By 
HOWARD S. FAWCETT 



A THESIS FOR THE DEGREE OF MASTER OF SCIENCE 
SUBMITTED TO THE FACULTY OF 

THE UNIVERSITY OF THE STATE OF FLORIDA 



June. 1908. 



FUNGI PARASITIC UPON ALEYRODES GITRI 



* \SAH li M,ii 



By 
HOWARD S. FAWCETT 



A THESIS FOR THE DEGREE OF MASTER OF SCIENCE 
SUBMITTED TO THE FACULTY OF 

THE UNIVERSITY OF THE STATE OF FLORIDA 

June, 1908. 



i-i^h 



UNIVERSITY OF THE STATE OF FI.OKIDA 
Special Studies No. i 



COXTFA'TS. 

PAGE. 

I. Introduction 5 

Statement of Work on Whicli the Thesis is Based 5 

Historical Review of Entomogenous Fungi 5 

Historical Review and Economic Status of Aleyrodcs citri R. & H 8 

n. ASCHERSONIA ALEVROniS WEBBER 10 

Discovery and Description 10 

History 10 

Methods of Introduction 11 

Germination of Conidia 12 

Cultures 1?> 

Infection of Aleyrodes citri from Cultures 16 

Distribution 1^ 

III. Aschersonia flavo-citkixa p. Henn 1~ 

Discovery and Description 1~ 

Comparison with A. alcyrodis IS 

Cultures l^^ 

Germination of Conidia !•* 

Super-parasite 21 

List of Localities in Florida 21 

IV. VERTICILLIUM HETEROCEAnUM Penz 21 

Discover}- and History 21 

Description 23 

Cullures 23 

Germination of Conidia 24 

Infection of Aleyrodes citri from Cultures 24 

List of Insects Parasitized, with Localities 25 

V. Si'HAEROSTlEBE COCCOPHII.A Til 25 

Description 25 

History 26 

Relation to San Jose and Other Scale Insects 27 

Parasitism on Aleyrodes citri 28 

List of Insects Parasitized, with Localities 29 

VI. M ICROCERA SP 29 

Technical Description 29 

Discovery ''0 

Cultures -0 

Infection of Aleyrodes citri from Cultures 32 

Germination of Conidia •^•' 

Variation in size of Conidia 33 

Distribution in Florida "'4 

VII. The "Brown Fungus" 34 

Discovery 34 

Description by Webber 34 

Brown fungus of Parkin ''.o 

Methods of Introduction 3o 

Distribution 36 

Supplementary Notes 36 

SuM^iARY 37 

BiBElOGRAPHY 38 

Explanation oe Plates ^ i 



LIST OF ILLUSTRATIONS. 

PAGE. 

Fig. 1.— Adult and egg of Alcyrodes citri facing 8 

Fig. 2. — Larvae and pupae of Alcyrodes citri facing 9 

Fig. ?,. — Conidia of Aschcrsoiiia alcyrodis 12 

Fig. 4. — Conidium of Aschcrsoiiia alcyrodis germinating 13 

Fig. 5. — Hyphae of Aschcrsonia flavo-citrina 19 

Fig. 6. — Conidia of Aschcrsoiiia flavo-citrina 19 

Figs. 7, S and 9. — Sporids of Aschcrsoiiia flavo-citrina 20 

Fig. 10. — Conidiophores and conidia of J'crticiUinin hctcrocladnm 2?, 

Fig. 11.— Spore-like bodies of I'crticilliuin hctcrocladuin 23 

Fig. 12. — Perithecium of Sphacrostilbc coccophila 25 

Fig. 13. — Ascus of Sphacrostilbc coccophila 25 

Fig. 14. — Sporodochium of Sj hacrostilbc coccophila 26 

Fig. 15. — Conidia of Sphacrostilbc coccophila 26 

Fig. 16. — Hypha and conidia of Micmccra sp 30 

Fig. 17. — Conidia of Microccra sp ''0 

Fie. 18. — Conidia of Microccra sp "^0 

Fig. 19. — Sporids of Microccra sp 33 

Figs. 20, 21, 22 and 23. — Cultures of Aschcrsonia alcyrodis Plate I 

Fig. 24. — Aschcrsonia flavo-citrina on Citrus leaf Plate II 

Fig. 25. — Aschcrsonia alcyrodis on Citrus leaf Plate II 

Figs. 26 and 27. — Cultures of Aschcrsonia flavo-citrina Plate III 

Figs. 28, 29 and 30.— Cultures of Aschcrsonia flavo-citrina Plate IV 

Fig. 31. — Vcrticilliuni hctcrocladuin on Citrus leaf Plate IV 

Figs. 32, 33 and 34. — Cultures of Vcrticilliuin hctcrocladuin Plate V 

Fig. 35. — J'crticiliiiiin hctcrocladuin on leaf Plate V 

Fig. 36. — Sphacrostilbc coccophila on Aspidiotus hcderac Plate VI 

Figs. 37 and 38. — Sphacrostilbc coccophila on Mytilaspis citric ola Plate VI 

Figs. 39 and 40.— Cultures of Microccra sp Plate VI 

Fig. ^1.— Microccra sp. on Citrus leaf Plate VI 

Fig. 42. — Brown Fungus on Citrus leaf Plate VII 

Fig. 43. — Super-parasite on Aschcrsonia flavo-citrina Plate VII 



FUNGI PARASITIC UPON ALEYRODES GITRI. 

LV 

Howard S. Fawcett. 
Plant Pathologist, Florida Agricultural Bxpcriuiciit Station. 



I. INTRODUCTION. 

Since taking up the investigation of Citrus diseases in the fall of 1905, 
in connection with work in the Florida Experiment Station, the author has 
given considerable attention to the study of the fungi parasitic on Alcyrodcs 
citri R. & H., and on scale insects. Since the beginning of the work three 
species of fungi have been discovered to be parasitic upon the larvae and 
pupae of Alcyrodcs citri; two of these, Aschcrsonia flavo-citrina. and an 
undetermined species of Microcera, were first noticed by Prof. P. H. Rolfs, 
and the third, J'crticilliuin hctcrocladuni, by the author. With the addition 
of these three, the number of known fungus parasites of this insect is in- 
creased to six, namely : 

1. Aschcrsonia alcyrodis Webber, 

'2. Aschcrsonia fla'Z'O-citrina P. Henn., 

o. J\viicilliuin hctcrocladuni Penz., 

4. Sphacrostilbc coccophila Tub, 

.1. Microccra sp., 

(). The sterile Prown fungus of Webber. 

Cultures of all these fungi except the Brown fungus have been grown in 
the laboratory bv the author. One of these, Sphacrostilbc coccophila, had 
been ]:)reviously studied in pure cultures by P. H. Rolfs, who published his 
results in Bulletin 41 of the Florida Experiment Station under the title of 
"A Fungus Disease of the San Jose Scale". For this reason a further study 
of this fungus in cultures was not undertaken, and it is, moreover, only 
rarely parasitic upon Alcyrodcs citri. 

It is the purpose of this thesis, after a brief review of previous investiga- 
tions of the fungus parasites of insects, to describe the results of recent study 
of the fungi that are parasitic upon Alcyrodcs citri in Florida. With the 
description of each fungus there is given its distribution and the names of 
its insect hosts. A bibliography of the six fungi is added. The illustrations, 
except Figs. 1, 2, and 42, are original. Technical descriptions and a general 
review of previous literature, when any such has been published, are in- 
cluded with the account of each fungus. 

ENTOMOGENOUS FUNGI. 

The fact that certain low forms of plant growth, such as fungi and 
bacteria, are at times the cause of the destruction of great numbers of 
insects, has created much popular as well as scientific interest for many 



6 l-'UNGI PARASITIC UPON ALKYRODKS CITKI. 

years. As early as 1754, according- to \l. C. Cooke, ^ a popular description 
was written by Father Torrubia of a fungus growing out from the bodies 
of wasps. Father Torrubia had collected specimens of this at Havana, 
Cuba, as early as lil!>. Cooke thinks that this fungus was Cordxccps 
spccoccpliala. He quotes Torrubia's account from Edwards' "Gleanings 
in Natural History,"" published in 1T5S, and says that this species represents 
the rather celebrated vegetable wasp which had a romantic history a century 
before. Cooke also gives an account of a species of Isaria, which had been 
known as early as 1T82 on the Sphinx moth.^ He mentions as many as 
Wi species, representing 39 genera of fungi, that have been found growing- 
upon various insects. The majority of these species are included by Cooke 
under .") genera : Cordyceps, with 48 species ; Laboulbenia, with .'U species : 
Isaria. with "34 species; Entomophthora. with 22 s]:)ecies : and Eminisa, with 
13 species. Since then man\- new genera have been added to the ento- 
mogenous fungi. Species of Cordyceps found on wasps, bees, ants, cater- 
pillars, and scale insects, have been mentioned by man}- scientists and 
popular writers from the last-mentioned date down to the present time. 
Cooke refers to the "History of Insects"' b}- Murra}-, published in 1838. as 
containing- interesting- accounts of fungi growing upon insects. 

The Tulasne brothers were ])robably among the first to study the para- 
sitism of these fungi. They published descriptions of some of them in 
l.S.-)7,- and of others in IS*).").^ Among those described in I860 was Spliacr- 
ostilbc cflccophila Tub. which is one of the species treated of in this thesis 
as sometimes parasitic ou .llryrodcs citri. The work of Pasteur on the 
flacherie of the silkworm, marked a great advance in our knowledge of 
insect diseases. This disease was due to a species of bacterium. Pasteur's 
work was taken up with the view^ of protecting the insect from parasitic 
growth, while most subsequent work has been carried on with the view of 
destroying- insect pests by means of their parasites. A work of much scien- 
tific imi)ortance was that of Roland Thaxter.'^ "The Entomophthoraceae of 
the l/nited States", published in 1888. The genera which he studied attack 
flies, beetles, moths, caterpillars, grasshoppers, and ])lant lice. 

Since the institution of Experiment Stations in the United States, ex- 
periments have been made with several species of fungi, with a view of 
using- them in combating insect pests. Up to this time the greatest degree 
of success has been attained in Florida, wd-iere the conditions of temperature 
and moisture are conducive to the spread of fungi. The use of fungi to 
combat insect ])ests has met with only liniited success in the Northern States. 
A numl)er of years ago the employment of a species of Sporotrichum for 
spreading disease among chinch-bugs received much attention. In 1895, 

'Vegetable Wasps and Plant Worms, pp. 41-4.1, London, IS92. 

"Cooke, Al. C. Vegetable Wasps and Plant Worms, pp. ,">, ?,?,, 41, 1?, 96, 11:^ ISH and 

281. 
' Memoirs of the Boston Society of Natural History. Vol. IV. No. 6. 



INTRODUCTION. 7 

S. A. Forbes'' of the Illinois Experiment Station gave a detailed account of 
cultures and infection exi)erinients carried on with this fungus. .\ few 
sentences from his discussion of the results are here quoted : 

The white muscadine will not spread among vigorous cliinch-bugs in the field in 
very dry weather to an extent to gi\'e this disease an\- practical \'alue as a means of 
promptly arresting serious chir.ch-lnig injury under such conditions. * * * 

It is most likel}- to catch in low spots, where the soil is kept somewJiat moist l)y 
dense vegetation, a mat of fallen herbage, or the like. '■' "■' '■' 

If decidedly wet weather follows upon its introduction, even after an interxal of 
several weeks, it is likely to start up and take visible effect; but continuous rains. 
depressing the \'ital energies of the insect, seem commonly requisite to its efficient 
action. 

Some investigation has been carried on with a numlx'r of other ento- 
mogenous finigi grown in pure cultures. G. F. Atkinson"' and R. hi. I'ettif' 
studied cultures of Cordyccf>s. Jsaria and Spcrolrichinii. R. H. Pettit in 
his bulletin isstied in ISit.") included a long bibliography of the literature on 
entomogenous ftingi, to which an\' one interested in th.e historv of this 
subject is referred. 

In lS!t;. 1'. II. Ivolfs.' in his bulletin "A Disease of tlie San Jose Scale." 
dem(_instrated that the ftuigus Sphacrostil'oc coccophila could be used in a 
practical way in combating the San Jose scale in Florida. In I'.XMi, a valu- 
able paper l)y J. I'arkin,'' "Fungi Parasitic on Scale Insects, "" gave a general 
review and the distribution of the fungus parasites of Coccidae and Ale}-- 
rodidae wh.ich h.ad b,een describ.ed in all countries tip to that time. He 
referred to a recent publication bv Gueguen'' in France, v.hich is said to be 
an exhaustive work on th.e fungus parasites of man and animals. A recent 
contribution l)v Fop'" on a new ftuigus parasite in AIartiiii(|ue that has 
saved the cocoamit industry of that island is also brieflv mentioned. 

In Florida, insects belonging to the orders Coccidae and Alevrodivlae 
are very suljject to attacks of fungi. In addition to the six fungtis parasites 
of .'llcyrodcs citri here treated of, there are two other fungi which are not 
found on this insect, although thev are quite common on scale insects of 
Citrus. These are () phioiicctria coccicola E. & E., and M yriaiii:;iinit diiriaci 
Mont., both of which are illustrated in Bulletin !)4 of the Florida Experi- 
ment Station. Webber also fottnd on the wax scale Ccroplasfcs floridcnsis. 
the fungus Aschcrsoiiia turhiiiata : and he mentions finding on variotis in- 



■* Experiments with the Muscadine Disease of the Chinch-bug. etc.. 111. Agr. Exp. Sta., 

Hul. :!S. isit.-,, 
' .-Xrtillcial cultures of an Entomogenous Fungus. Bot. Gaz., Vol. XIX. pp. 129-14.'). IS04. 
"Studies in Artilicial Cultures of Entomogenous Fungi. Cornell Univ. Agr. Exp. Sta. 

Bui. 97. isu.-). 
A-\ Eungus Disease of the San Jose Scale. Fla. Agr. Exp. Sta. Bui. 41, lS<,i7. 
Wnnals of Roy. Bot. Gard. Peradeniya, Vol. :j. Part 1. 
''Gueguen, F. Le.s Champignons parasites de I'homme et des animaux, pp. :>.j2, Paris, 

1904. Bot. Centralbl., XCVI, p. 644. 
"Dop. P. Bull. Sci. France et Belgiquc, XXXIX, p. i:!.".. 190.-.. Bot. CentralliL, XCIX, 
p. ."iO.-.. 



S FUNGI PARASITIC UPON ALEVRODF.S CITRI. 

sects other Aschersonias, which, as far as we know, he has not identified. 
Prof. H. H. Hume sent to the author in 19\)() a species of Asclicrsonia found 
on what appeared to be an Alcyrodcs on the leaves of Ucx Dahoou. It is 
quite probable that further observation will reveal a number of other species 
of fungi parasitic upon insects of these two orders in Florida and the ad- 
joining" States. 

AI.KVKODI'S CITRI. 

This insect, the larval and pupal stages of which are parasitized by the 
fungi to be discussed later, has been a serious pest of orang-e groves in 
Florida and the adjoining- States for a number of years. It had been ob- 
served by C. A'. Riley in 18TS in the greenhouses at the L^nited States De- 
partment of Agriculture at Washington. In IHS."). l\lr. Ashmead wrote an 
account of it for the "Florida Despatch", in which he gave it the name of 
Aleyrodcs citri. In 1895, Riley and Howard^- first described this species 
in "Insect Life". In this publication it is reported as having been received 
from Mississippi, Louisiana. Xorth Carolina and many points in Florida. 
Gainesville and Crescent City are ])laces mentioned at which it had been 
studied by Jas. Voylc and H. G. Hubbard, before LS9o. It is also stated that 
during the years 1S9-2 and LS93 it had so multiplied in parts of Louisiana and 
Florida as to deserve immediate attention. It is of interest here to note that 
it was about this time, L89;), that Webber discovered the first fungus para- 
site of this insect. 

This insect is not a true fiy. as the name might implw but belongs to 
the Order Flemiptera. which also includes the plant lice and scale insects. 
The following summary of the life-history of Alcyrodcs citri is from Bul- 
letin 8<S of the Florida Agricultural Experiment Station, b\- E. W. Berger : 

There are three well-defined broods of the whitefly, with an interval of several 
days to several weeks between each brood, when few or none are seen on the wing. 
The first brood generally appears some time during March, April or Ma}-; the second 
during June, Jul_\ or August; and the third during September and October. 

Larvae and pupae of the whitefiy are to be found on the under surfaces of the 
leaves, and seldom elsewhere. The larvae are scale-like and closel_\- appressed against 
the leaf. They vary in size from the very young, just visible to the unaided eye. to the 
fully matured larvae which measure about one-si.xteenth of an inch in length. 

The larvae are wliite and translucent with a tinge of yellow, and almost invisible 
upon the leaf. The pupa (Fig. 2, No. 8) is the transformation stage from the larva 
to the adult winged fly. The pupae are readily visible as yellowish-white, plump, oval 
bodies with a dark reddish spot on the back. From the pupa emerges the adult winged 
fly. The little white cases, with a T-shaped split on the back, found on the under 
surface of a leaf, are the empty pupa cases from which the adults have emerged (Fig. 
2, No. 10). The eggs (Fig. 1, Nos. 3 and 4) are just visil)le to the unaided eye as a 
fine dust upon the under surface of the leaves. An ordinary hand lens will show 
them as little egg-shaped bodies much resembling grains of wheat. * * * 



" Rile.v, C. v., and Howard. L. O. Insect Life, U. S. D. A., Div. of Entomologv, Vol. V, 
No. 4, p. 220, Washington, D. C, 1S93. 




Fig. 1. — Ai.EVRODES ClTKI.'" 

, , ■ 1 XT "■. p-cro-- "Mo -I Kocr-shell ; No. 5, Claspers at tip of 
^°- l.:i::i:; ^:l^'^'S^'^^n,eJf^^^l 1ji?'.ar.i,i o, front w.ng. 

Insects sometimes mistaken eor AeEvrodes citri. 
No. S. Larva of Alcyrodcs floridcusis; Nos. 9 and 1... Margin of larva; No. 11. Larva 

of Lrcaiiiuiii Iu-st>criiii(in. 
^F^7Fla. Agr. Exp. Sta. Bnl. iu. l.y H. A. Gossard. 




Fig- 3-— Alevrodes citri.* 

^°ut £.^rH;if?LSf;'^Li:^u:^;"ssts:; t- i \r''- --r'. ^^-^ 

arva: No. 7, Vasiform orifice of fourt^kag xf f 'p,fp^ 'no Y^h,'] "^"""'^^ 
l^om pupa-case; No. 10, Empty pupa-case ' ^ ' -^''"'^ emerging. 



From Fla. Agr. Exp. Sta. Bui. 67, by H. A. Gossard. 



INTRODUCTION. 9 

Twenty thousand eggs have been estimated on a hirge orange leaf. From observa- 
tions made in the laboratory, egg-laying begins when the female is from eighteen to 
thirty hours old ; and from seventeen to twenty-live eggs are deposited. These eggs 
are generally all laid within twenty-four hours after the first egg has been laid. Her 
length of life has been estimated at from three days in warm weather to three weeks 
in cool weather, and the complete length of life cycle from egg to adult is from forty 
or fifty days in summer to six months in winter. > 

The origin of the whitefly pest in Florida i.s only a matter of coii- 
jectfire. It is not definitely known whether it is a native species or was 
introduced from the East. A recent report that Jlcyrodcs citri has been 
discovered in Asia gives some weight to the latter view. 11. A. Gossard, 
in Bulletin (u of the Florida Experiment Station, "The W'hiteH}", IIH):;, said 
with regard to its advent in Florida : 

The fly seems to have been first known in Florida throughout the region comprised 
in Volusia, Alarion, Lake, Alachua, and Orange counties; from which, I have little 
doubt, it was transferred to Manatee county and to local centers almig the northern 
borders of the State. 

It had therefore become widely distributed before it attracted any consid- 
erable attention. At the present time it is widely distributed in many pai"ts 
of Florida, and is spreading slowly to parts not before infested, in spite of 
the work that is done b_\' the growers to kee]) it out of the groves. 

Several investigations are being carried on at the present time bv the 
Florida Experiment Station, and by the I'nited States Department of Agri- 
culture in order to work out practical methods of controlling the pest. 
Spraying with insecticides, fumigation with hydrocyanic acid gas under 
tents, and infection with fungus parasites have all been used. Fumigation 
and fungus infection are the most ])romising remedies known at the present 
time. The use of the fungus parasites in destroying" this insect will be 
briefly discussed later, when the various fungi are described. 

The most serious injury caused by the whitedy is the sooty mold that 
always follows the insect. This is a species of Aleliola, a soot-colored 
fungus that lives in the hone^dew secreted by the whitetl\- larvae. Since 
the larvae are found upon the itnder surfaces of the leaves, the honevdew 
collects upon the upper surfaces of the leaves below and furnishes a suita- 
ble medium for the growth of Aleliola. The sooty mold spreads in a black 
layer over the surface. The fruit is also blackened, so that it nuist frequently 
be washed before it is shipped. The vitality of the tree is lowered, not 
only by the loss of the nourishment sucked out by the insects, but also by 
the shutting off of the sunlight from the surfaces of the leaves. An account 
of this fungus is given by Webber in Bulletin lo of the Division of \'egetable 
Physiology and Pathology, Washington, D. C. 



10 FUNCl PARASITIC UPON ALKYKonivS CJTKI. 

II. ASCHERSONIA ALEYR( )DIS WEBBER. 

This species was first discovered by H. J. Webber in August, 1893, at 
Crescent City, in the grove of J. H. Harp. Mr. Webber'- pubHshed a pre- 
hminarv notice of the entomogenous nature of this fungus in 1894, referring 
it to Aschcrsoiiia faliifciisis Alont. In ]89(i. under the same name, he 
mentions it in the buHetin, "The Principal Diseases of Citrus Fruits in 
Florida".'-' Finding it after further study to be a distinct species, he de- 
scribed it in 1897 in his bulletin, "Sooty Mold of the Orange and its Treat- 
ment," as Jschcrsonia alcyrodls,'^'^ as follows: 

Aschcrsoiiia alcvrodis Wel)l)er. Stroma liypopliyllous. depressed hemispherical, 
pinkish buff or cream colored, coriaceous, 1 — 2i/^mm. in diameter; mycelial hypothallus 
grayish white, forming a thin membrane closely adhering to the leaf and extending 
about 1 mm. beyond the stroma ; perithecia membranaceous, at first superficial, later 
becoming immersed, irregular, reniform or orbicular in mature specimens, and opening 
by small, round, or elliptical pores or slits; basidia crowded, filiform, slender, con- 
tinuous, 28 — 40 microns long, 0.94 — 1.5 in diameter; paraphyses abundant, slender, 
projecting beyond the basidia, 6,5—100 microns long, M— 1 micron in diameter; spor- 
ules fusiform, continuous, mucilaginous, hyaline, sometimes obscurely .'! — 4 guttulate, 
94 14.1 microns long by 0.94 — 1.S8 microns wide, very abundant and erumpent, form- 
ing conspicuous coral red or rufus masses. (Parasitic on Alcymdcs citri R. & H. infest- 
ing citrous leaves in Florida). 

HISTORY. 

Some species of Aschersonia have been reported to be conidial stages of 
the genus Hypocrella, an Ascomycete. Massee'"' speaks of having shown 
that the ascigerous forms of species of Aschersonia were produced on fallen 
leaves on which the conidial stages had grown. Parkin'^' also mentions this 
genus as the probable perfect stages of species of Aschersonia and refers 
to a species of Hypocrella (H. Raciborskii) described by Zimmerman.''' 
with a conidial stage referable to Aschersonia. Xo ascigerous forms have 
as yet been discovered in connection with the Aschersonias in Florida. 

In 1905, F. S. Earle'^ reported Aschcrsoiiia alcyrodis on Alcyrodcs 
citri in Cuba. In 190(), J. Parkin'-' reported finding an Aschersonia on sev- 
eral undetermined species of Aleyrodes in Ceylon, which closely resembled 
Aschcrsoiiia alcyrodis. He said, "Numerous forms of Aschersonia have 
been found in Ceylon on species of Aleyrodes and Lecaniuiu". In February, 
1908, Cook and Home-" reported Aschersonia alcyrodis on Aleyrodes citri 
and on Aleyrodes Jioii'ardii. in Cuba. 



'■■^Webber, H. J. Journal of Mvcologv, Vol. VI, No. 4, p. ,-563, 1894. 

" Webber, H. J. Div. of Veg. Phys. & Path., Bui. 8, p. 27, Washington, D. C, 1896. 

"Webber, H. J. Div. of Veg. Phys. & Path.. Bui. l,!, p. 21, Washington, D. C, 1897. 

'"Massee, G. Jour. Bot. Vol. 34. p. 151. 

'" Parkin, J. Ann. Rov. Bot. Card. Peradeniva, Vol. Ill, Part I, pp. 29 and 35. 1906. 

" Zimmerman. Centralb. fur Bakt., Abth. II, Vol. VII, p. 872. 

'" Primer Informe Anual de la Estacion Central Agronomica de Culia, 1904 and 1905, 

p. 169, 1906. 
''Annals Rov. Bot. Card. Peradeniva, Vol. Ill, Part 1, p. 36, 1906. 
""Cook, M. t., and Home, W. T. Cuban Exp. Sta. Bui. 9, p. 31, 1908. 



ASCIIKKSOXIA AI.l-A KODIS. ' 11 

Previous to Webber's publication.-^ the entomogenous nature of the 
genus Aschersonia was not known, although up to that time there were 19 
species of this genus described, as recorded in Saccardo's "Sylloge Fun- 
gorum". This species was therefore the first known parasite of Alcyrodcs 
citri. and was probably the first fungus that had been reported on any 
species of Aleyrodes. In the course of his investigations on the sooty mold, 
Webber reported that he had found three other species of Aschersonia. 
parasitic on other insects in Florida ; one of which was Aschersonia tiir- 
binata on the Wax Scale [Cerophistes floridensis Comst.). The others 
were not determined by him. In 1(S9T, when he wrote his bulletin on sooty 
mold, Webber reported that Aschersonia aleyrodis was found in Florida 
at Crescent City, Bartow, Panasofl^kee and Gainesville. He also stated that 
no sign of the fungus was apparent in groves infested with Aleyrodes citri 
at ( )cala, Orlando, Evinston and Ormond. In the same bulletin, the de- 
velo])ment of the fungus, the probable method of spore dissemination, and 
the methods of introducing the fungus on the orange trees, are discussed 
at some length. The description of the development of the fungus in the 
next ])aragra])h is taken with slight changes from this bulletin. -- 

Tlie first indication of tlie et¥ect of the fungus on the larva of tlie whitefly is 
tlie appearance of slightly opaque, yellowish spots unusually near the edge of the 
larva. In the early stages of infection the larva becomes noticeably swollen, and appears 
to secrete a greater abundance of honeydew than normally. As the fungus develops, 
the interior organs of the larva appear to contract away from the margin, leaving a 
narrow circle, which becomes filled with h\'phae. Shorth- after this the hyphae burst 
out around the edge, forming a dense marginal fringe. This may form all around 
the larva at about the same time, or de\-elop at one portion of the margin sooner than 
the others. Death usually ensues, it is believed, l^efore the hyphae burst out. Tai- 
fungus does not --pread over the leaf to any extent, but grows upward in a mass, 
gradually spreading over the larval scale. It is not uncommon to find the pycnidia, with 
their bright coral-red masses of sporules, formed in a circle around the edge of the 
larva while it is yet visible. .\s the .Aschersonia develops, the hyphae spread over 
the larva forming a dense compact stroma, which ultimately entirely envelops the 
larva. The stroma in this stage is thin and disk-like, the fructification being usually 
borne in a circle near the edge. The hyphae. which make up the main mass of the 
stroma are from :;..") to T.,"i micro-millimeters in diameter. Within the body of the 
insect and near the pycnidia they are somewhat smaller. 

METHODS OF INTRODUCTION. 

Two methods of introducing the fungus into groves infested with 
Aleyrodes citri were used by \\'ebber with fair success. ( T) Pinning 
fungus-bearing leaves into trees infested with .ileyrodes citri. in such a 
way as to cause the fttngus spores to come in contact with larvae not vet 
infected. (2) Planting small trees with fungus infected larvae in a grove, 
so that the fungus-bearing leaves came in contact with the leaves on which 



" Webber, H. J. Div. of Veg. Phvs. & Path.. Bui. K!. 11. 2i). Washington. D. C. 1897. 
''Webber, H. J. Div. of Veg. Phvs. & Path.. P.ul. 1.!. pp. 2:!-24, Washington, D. C, 
1897 



^■2 PVSC.I TAKASITIC UPON ALRYRODICS CITRI. 

it was desired to start the fungus. Further methods of introducing this 
Aschersonia by spraying the trees with water containing fungus spores, 
obtained either from previously infected larvae or from artificial cultures, 
have been recently carried on by E. W. Berger^"'- of the Florida Experi- 
ment Station. Webber--* had tried infecting larvae by spraying a mixture of 
conidia in water, but had failed to reproduce the fungus in this way. E. W. 
Berger has found that to succeed with this method it is best to have a spray 
jnini]) that contains no copper parts, and that has also not been previously 
used for spraying fungicides or insecticides. Fairly good infection of this 
fungus has been obtained by Berger, by the spore-spraying method, at St. 
Petersburg. Leesburg. Xew Smyrna. Gainesville and Lake City. The fact 
that infections mav be made from cultures that have grown under artificial 
conditions in the laboratory for long periods of time, suggests the possi- 
bilit\- of using these cultures in a practical way at the very beginning of 
the rainy season, when fresh fungus on leaves is hard to obtain. Consid- 
erable quantities of this fungus may be grown artificially on various media, 
as will be shown in the following pages. 

CKKMINATION OF C0NI1)I.\. 

Conidia of this fungus were germinated in hanging drop cultures of dis- 
tilled water, tap water, and various solutions of glucose. In all of these 
cultures the germination was very slow, scarcely ever beginning in less 
time than -^o hours. Germination in distilled water and tap water was very 
feeble, while that in solutions of glucose was much stronger, as is explained 
more fully under the germination tests for Aschersonia fJavo-citrina. 

Trials were made at various times to germinate spores in hanging drop 
cultures from pustules that had dried in the atmosphere of the laboratory. 
The following is a record of these tests : 

1. On November 10. IDOd. cultures were made from 
leaves collected on October 12, l!M)(i, which had remained 
n in the laboratory 28 days. The tests were made in glucose, 
// in distilled water, and in tap water. On December 11 (31 
(/ days) sporids formed in 5 per cent, glucose. The growths 
Fig. 3. in distilled water and in tap water had not proceeded far. 

^""o'!^',*^ ,?^ -iNcA/c- .> Oj-, Januarv 5, 1907, cultures were made from leaves 

so/u'f (I If'}/) iirt IS, *^ •' 

X iiK)0. collected October 13, 1906, which had remained in the 

laboratory for 8.") days. The test was made in distilled water. Xo germina- 
tion took place. 



'^Fla. Exp. Sta. Bui. 88. pp. 57-63, 1906 
'' Webber, H. J. Div. of Veg. Phys. & P 



Path., Bui. 13, p. 26, Washington, D. C. 



ASCHEKSOXIA ALEYKODIS. 13 

;>. On April IS, 1901, cultures were made in tap water from leaves 
collected October 12, 1906, which had remained in the laboratory 189 days. 
No germination took place. 

4. On April 18, 190T. cultures were made in tap 
water from leaves collected on December 13, 190(5. Fig. i. conidiiim of .4.-c/ier- 
which had remained in the laboratory 128 days. No uTrperTentgu^^^^^ 
germination took place. tion at 25°c.. x looo. 

5. On April 18, 1907, germination trials were made from a culture 
isolated December T, 190(). which was transferred to potato on January 14, 
190T, and had not entirely dried out. A few spores germinated. 

Cl'LTUKKS. 

I'ure cultures of Asclicrsoiiia alcyrodis were first olitained in January, 
1907. On December 7, 190G, petri dishes of neutral .") per cent, glucose agar 
were poured. These were made by introducing into the melted agar a 
platinum loop, that had been thrust several times into a test-tube containing 
spores from several stromata shaken up in sterile water. In the first dilu- 
tion, on January .") (29 days), at a temperature of lo° to 2-")° C, minute 
fungus mycelia appeared, yellow in the center, with a fringe of delicate 
white hyphae projecting outward. On January 8 (32 days), the largest 
of these had turned red in color. They were raised, hemispherical, and 
had the upper surface dotted with little white lumps. Larger stromata were 
2 to 4 mm. in diameter. ( )n January l.') (39 days) the stromata were .5 
to 7 mm. broad, with a wide fringe of straight hyphae ])roiecting outward 
over the agar. The stroma l)v this time contained p}cnidial cavities with 
spores (Plate I. Fig. 20). 

On April 10. 1907, this fungus was again isolated. Leaves were picked 
at ( )rlando, on April (!. Pustules were broken up in water in a watch-glass, 
and a dilution set of three pe'.ri dishes A, P> and C, was poured with agar 
(1 ]Der cent, normal acid to phenolphthalein ) , to which 5 per cent, glucose 
sugar had been added. Petri dish A was overrun with bacteria and quick- 
growing fungi. Petri dish ll contained, on April 2() ( Ki days), about 50 
centers of growth just beginning, and a few bacteria. Petri dish C, on 
April 26 (16 days), contained no visible growth. ( )n Ala}' 11 (31 days), 
C contained a fine growth of 11 mycelia, which proba1)ly first showed a few 
days before. No further record was kept. 

( )n September 23. 1907. t.his fungus was isolated for the third time in 
petri dish cultures A. P) and C. Four or five small pustules were shaken 
up in ? cc. of water imtil it became milky in appearance. Five loopfuls were 
washed into A, etc. A was contaminated with other fungi, C developed one 
mycelium of A. alcyrodis, and one of another fungus, l^etri dish B devel- 
oped a pure culture as follows: — On October 8 (15 days), one point of 
growth was just appearing. ( )n October 18, there were four mycelia, five 
to six mm. in diameter, with rings of reddish pycnidia ; and seven others 
just starting. On ( )ctober 28 (35 days), twenty verv red pustules with 
abundant spores and light gray fringes of outgrowing h\phae had de- 
veloped. 

From lliese isolation tests, it appears that on 5-10 per cent, glucose agar 
in the laboratory, it requires from ."JO-IO da> s for the fungus to mature a 
pustule and produce pycnidia. This time corresponds somewhat closely 
to the time for the fungus to develop u]^on larvae of Aleyrodcs citri. as 



14 FUNCI i'AKASITiC LPOX Al.KNKODKS CITRI. 

shown by the infection experiments of E. VV. IJerger. (See Bulletin 88. 
Florida Experiment Station, pp. .■">:, .■)8.) The fungus is extremely slow in 
developing in the petri dishes, thus increasing the liability to contamination 
with other fungi and bacteria. Its slow-growing habit demands therefore 
a strictly pure culture, since the rapidly growing fungi and bacteria will 
otherwise crowd it out completely. 

The many previous failures of the author and of others before him to 
grow this fungus in cultures, were probably due to the fact that the petri 
dishes were rejected too soon, or were allowed to dry out before the spores 
had time to form mycelia and stromata. This fungus was transferred from 
petri dish cultures to test-tubes of sweet potato ( I'late I, Fig. 22), Irish 
potato, rice, white cornmeal (Plate I, Figs. 21, 2:)), and bread. On all 
of these media, the growth was similar in general appearance to the growth 
of Jschersonia fhvi'O-citrina, except that the color of the stroma and spore- 
masses was red instead of yellow. The most luxuriant growth was on sweet 
potato plugs. The characteristic red color of the fungus stroma rarely ap- 
peared on Irish potatoes. This would seem to indicate that sugar was 
necessary for the proper development of both the red pigment of Aschcr- 
sonia alcyrodis, and the yellow pigment of . /. flavo-citriiia. 

The growth on sweet potato plugs is given here for comparison with 
the growth of Aschcrsoiiia flcwo-cifrina on this same medium. 

1. On April 8, 1907, spores were transferred from cultures made on 
January 14, 1907. The spores were streaked onto the surface of the sweet 
potato plug with a platinum needle. On April 17, abundant growth all 
along the streak had begun. ( )n Aj^-il "ili, a large raised red mass. 40 mm. 
long, had formed. 

2. On April 8, s]>ores were transferred as in Xo. 1. ( )n April 1^, very 
abundant growth bad started, and on April 2(). a very large red mass had 
formed. 

3. On April 8, s])ores were transferred as in Xo. 1. ( )n April 17, good 
growth with thickened points had started. ( )n April "^(i. a verv large mass 
of red growth had formed. 

4. ( )n April 8, spores were transferred as in X"o. 1. On April 17. a 
cream-colored to orange, mealy appearance was evident, spreading to each 
side of the streak. ( )n April 'il), an abundant growth, red in color, had 
formed. 

EXPERIMENTS IN CROWING ASCHERSONIA AI.EYRODIS IN LARGE (JUAXTITIES. 

In April, 1907, experiments were begun in order to grow large quantities 
of fungus for infection of Alcyrodcs citri. Ten large moist chambers, nine 
wide-mouthed bottles of .")■;»() cc. capacity, and four petri dishes five inches 
in diameter, were prepared with sweet ])otato medium. The potatoes were 
washed, peeled, washed again and put through a meat chopper. This 
ground-up mass was then washed in running water to get out fine particles, 
and the moist medium was sterilized in the autoclave at llO'' C. for about 
20 minutes. After sterilization, the medium appeared well cooked. 

On April 5, these were inoculated, in the transfer closet, by spraying the 
surface of the medium with a band atomizer with a mixture of conidia in 



.\SCHEKS!:)NIA ALEYK(M)IS. 15 

sterile water. The conidia were obtained from an old culture of the fungus 
grown on sweet potato. All of the cultures, except two large petri dishes, 
finally became contaminated with a growth of bacteria. This was probabh- 
due to insufficient sterilization of the interiors of the large masses of medium 
•'n the moist chambers and in the 500 cc. bottles. The fungus in the two 
petri dishes which were successful, appeared in 15 days as a creamv white, 
tcit-like growth over the surface of the medium, with no red color. A'er\- 
little red color appeared later, and no large spore-masses developed. It 
seemed that the spores had been sown too thickly over the surface to develop 
the characteristic pustules with pycnidial cavities. This experiment was 
practically a failure. 

On June 12, IMo;, five bottles of ground-up sweet potato, and one bottle 
of bread, which had been sterilized in an autoclave for about half an hour 
at 120° C, were inoculated by streaking the surface with a large platinum 
loop from cultures ])reviously made on sweet potatoes. Three of these 
were successful, two on sweet potato, and one on bread. The notes on 
these are as follows : 

1. On June 12, 1!)07, a culture on bread was made from a culture on 
sweet potato plug, which had been transferred three times from an isolation 
culture in petri dish poured December 7, IDOli, and described above. 

Transfers had been made on January 14, 1!M)T, April 10. lilOT, and June 
•y. 1!):)7. On June li), the fungus was growing well at one point. 

On July 1, a large raised mass ^^ inch in diameter was formed. ( )n 
July 20, a large area 1 inch in diameter, and red in the interior, with al:)un(l- 
ant spores, had grown. 

2. On June 12, IDO*, a culture on sweet potato was made from another 
culture with same history as above. On June 1!), the fungus had started at 
seven points. On Jul\' 1, masses 1-3 inch in diameter had fc^rmed on one 
side of the bottle. 

3. ( )n June 12, 1!H)7, a culture on sweet potato was made from a sweet 
potato plug, which had been transferred once from a petri dish culture of 
April 10, 1907, being transferred on June 3, 19o;. On June 11), the fungus 
was just starting at three points. On July 1, raised areas one inch in 
diameter had formed on one side. On July 20, a growth 1^2 inch in diam- 
eter had formed. 

On June li), six bottles of sweet potato and one of bread were inoculated 
from sweet potato test-tube cultures which had been transferred twice from 
an isolation culture made not later than April 10, 1907. Four lM)ttles de- 
veloped pure cultures. 

1. On June 19, 1907. the surface of a bottle of sweet potato medium 
was streaked with a small needle from a culture of June 3, 1907. ( )n Julv 
1, three or four areas of growth had appeared. ( )n July 2<), a good white 
growth had formed all around the base of the potato plug. 

2. On June 19, 1907. sweet potato medium was streaked as in Xo. 1, 
from a culture n^ade June 3. 1907. On July 1, a good growth had fornied 
on the surface, white and lumpv in appearance. On Julv 20, the growth had 
formed all over the surface of potato, and spores had grown in the pycnidia. 
On August 12, spores were very abundant. 

3. On June 19, 1907, sweet potato medium was inoculated Ijv shaking 
up conidia in a test-tube of water and pouring it over the plug. ( )n Julv 1. 
very small areas on side of glass appeared. On August 12, areas of large 
size ]-:ad grown, but no conidia could be found. 



16 I'UNC.I PARASITIC UPON AI.KVKODlvS ClTRl. 

4. ( )n June 1!>. l!)()i, l)rea(l medium was inoculated as the sweet potato 
in Xo. ;'), with conidia from a culture made on June 3. 1907. The old potato 
])luo- from the same culture w^as also dropped in. ( )n July 1, a good growth 
out from old plug had started. On July <?(». growth over nearly entire 
surface, reddish in ]xitches, had formed. ( )n August 1'2, no conidia could 
he found. 

IXFl'XTKf.X ()!•' AI.IvVRODKS CITKI FROM CL'I. TURKS. 

Tn two localities in the State, this fungus was started on larvae of 
.Uexriuics cifri, from cultures which had grown for some time on culture 
media in the lahoratory. This infection work was done by E. W. Berger 
at Gainesville and St. Petersburg, from cultures grown liy the author. 

Tlie following records are taken from E. \\'. P)erger"s held notes: 

1. August 10, 19()~. GaiiK-svillr. From culture ou sweet jiotato uiade Juue 2'.',. 
having been isolated not 1,-iter than April ](), 1907. Culture mixed up in water and 
sprayed with hand spra>er on under surface of leaves on lower branches of an orange 
tree. October 6, no fungus found. On November 1C', three pustules of fungus found. 
On December .'il, sprinkling of pustules evident. A])\-\\ .'!, lOOS, quite a sprinkling of 
fungus pustules evident. 

2. August 10, 1007. Gainesville, Florida. From old cultures in three test-tubes. 
Age of cultures unknown. No start by Aprd ."!, 1908. 

:;. .\ugust 1."(, 1907. St. Petersburg, Florida. From culture made June 19, on 
bread in large liotlles ;nid transferred twice before from cultures isolated not later 
than April 10. The culture was washed to fine pulp in water and strained. One and 
a half to two quarts of the liquid was used. Sprayed on the under side of leaves with 
a compressed-air sprayer. On October 23, quite a sprinkling of fungus was found. 
Some twigs had several leaves well covered with pustules, mainly on the newest 
growth. On December 10, about the same condition. On February S, 1908, an abund- 
ance of fungus was found on northwest side of tree, and fresh pustules were appearing. 

4. August 15, 1907. St. Petersburg, Florida. From culture on sweet potato, 
made June 19, 1907. Culture washed to fine pulp and strained. Two quarts of solu- 
tion were sprayed on with compressed-air hand sprayer. On October 23, a good 
sprinkling of fungus was found with some leaves well covered. Best catch was on 
west side, mainly on newer growth. On December 10, 1907, pustules more mature, 
l)ut apparently not spreading. On February S, 1908, an ainmdant catch of fungus was 
evident. 

."). August 1."). 1907. St. Petersburg, Florida. From a mi.xture of two cultures, 
one of Aschcrsdiiia a Icy rod is made June 19 on potato plug and transferred twice 
before; the other of .Isclicrsoiiia flavo-citriiia made Ma}- 23, on sweet potatoes in a 
bottle, and transferred twice before. Cultures mixed, washed and strained, making- 
one gallon of the solution. On October 23, fair sprinkling of the fungus, probably 
onl}- the red. mainly on newer growth. On December 10, same, but pustules more 
matured. On February s, 1908, all red pustules, no yellow present. 

(■). .August 14, 1907. St. Petersburg. Florida. From culture made June 19. 1907, 
and transferred twice before. No start by February 8, 1908. 

7. August 14, 1907. St. Petersburg, Florida. From culture made April 8, 1906, 
which had been dried for two months. The fungus had been transferred twice before. 
Isolated from petri dish culture made December 7, 1906. No start of fungus by Feb- 
ruar\- 8, 19()S. 



ASCHKRSONIA FL.WO-CITRINA. 17 

DISTRIBUTION OF ASCHERSOXIA ALEVRODIS IX 19U8. 

In Florida it has been reported from or seen at the following- places, 
occurring only on Alcyrodcs cifri : 

Alva, Apopka, Bartow, Bradentown. Buckingham, Citra, Fort ]\lyers, 
Gainesville, Glen St. Mary, Jacksonville, Lake City, Leesburg, Manatee, 
Mcintosh, New Smyrna, Oneco, Orlando, Oviedo, Palmetto, Sarasota, St. 
Petersburg, St. Augustine. 

Outside of Florida it was reported l)y Cook and Plorne from Cuba on 
Alcyrodcs citri R. & H., and Alcyrodcs lun^'ardii Ouaintance ; from Java 
by Kirkaldy & Kotinsky. doubtfully upon Alcyrodcs loiii^iconiis Zehntner; 
from Brazil bv the same authority, doubtfulK' uptm .Hcyrodcs horridiis 
Hempel ; from Cevlon bv Parkin on various undetermined species of Aley- 
rodes ; and from Jamaica l\v Cockerell under the name of Aschcrsoiiia taliit- 
ciisis Mont., which is i)rol)ably , /. alcyrodis \\ el)l)er. 

III. ASCHERSOXIA FLA\()-C1TR[XA P. HENN. 

The discovery that Aschcrsoiiia fhiro-citrina V. Plenn. was ])arasitic 
upon Alcyrodcs cifri R. & H., was made by P. II. Rolfs-^' by means of 
specimens sent to him from J. F. Adams, \\'inter Park. Fla., in September, 
190(3 (Plate II, Fig. 24). Later in the same year I{. \\'. Berger found this 
fungus efifectively parasitizing Alcyrodcs cifri in several other localities in 
the eastern part of Florida, and since that time he has succeeded in intro- 
ducing it into still other localities. This fungus was first described by P. 
Hennings in 1002, as occurring on leaves of Psidium from the botanical 
gardens of Sao Paulo, Brazil. Xo mention is made by him of any insect 
associated with its presence on the guava leaf. This species is described by 
Hennings-'^ as follows : 

Aschcrsonia flavo-citrina P. Henii. Stromatibiis carnosis. hypophyllis, subdis- 
coideo-pulvinatis vel hemisphaerico-depressis, citrinis, 2 — 2.5 mm. diameter, pruinosis. 
superne punctulato-pertusis, intus subaurantiis, subiculo membranaceo, flavo; pycnidiis 
immersis oblongis, paraphysibus filiformibus. fle.xnosis, byalinis 140-180X1 — 1.5 micr., 
continuis ; conidiis fusoideis, utrinque acutis, continuis, liyalinis. 12-18X2 micr,; con- 
idiophoris brevibus, liyalinis, fasciculatis. 

It was found in the botanical garden of Sao Paulo on a leaf <>f Psidium 
sp., October, 1!»01. 

That Aschcrsoiiia fhri'o-cifrma ma\' Ijc able to attack other .\le\rodidae 
besides A. cifri is shown b}- the fact that in June, 1!>(>L Stene of the Rhode 
Island College of Agriculture, was able to infect larvae of Alcyrodcs vaf>or- 
arioritm. on cucumber leaves in the greenhouse, from material sent from 
Florida by E. W. Berger.-" These are the only two species of Aleyrodes on 
which it has yet been observed. It is probal)le, however, that further ob- 



"" Rolfs, P. H. Fla. Exp. Sta. Rept.. p. xvi. 1907. 

-"Hennings. P. Hedwigia, Vol. 41, p. .^07. 1902. 

■' Berger, E. W. Fla. Agr. Exp. Sta. Rept., p. xx.xiv, 1907 



18 FUNGI PARASITIC UPON AI.KVKODF.S ClTRI. 

servations will reveal its presence on other Aleyrodidae native to the woods 
of Florida. 

COMPARISON OF ASCHKRSONIA FLAXO-CITklN A WFl'll A. AI.IAKOOIS. 

The two species are very much alike in their general appearance, and 
also approach each other closely in the measurements of their structural 
parts. The most evident distinction is in the color. J. aJcyrodis is usually 
red or pink, while A. fhri'O-citrina is yellow and never contains any reddish 
pigment. The stromata of A. alcyrodis, under similar conditions, average 
less in diameter, and the pycnidial cavities are usually more sunken than 
in A. flaz'o-citriiia. The spores of A. alcyrodis also average a little smaller 
than those of A. flai'O-a'trliia. Measurements of Florida specimens show 
that the spores of A. alcyrodis are about !» — 14X2 — 3 microns, while those 
of A. flavo-citriiia measure about 12 — loX- — 3 microns. Cultures of these 
two Aschersonias on similar culture media, und.er similar conditions, showed 
them to be distinct forms. 

CULTURES. 

Soon after the discovery of . /. flaro-cifriiia on Alcyrodcs cifri. attempts 
were made bv the writer to produce cultures of this fungus on ordinary 
culture media. Attempts to isolate Aschcrsoiiia alcyrodis on neutral pep- 
tonized agar had been made without success. The beneficial effect of the 
addition of sugar on the germination of the spores in hanging drops had 
been noticed. On the addition of 10 per cent, glucose to the agar, petri dish 
cultures of A. flavo-citritia were successfully grown. The growth on 10 
per cent, glucose agar, poured on Septeml;er 14, l!»n(;, at a tem])erature of 
about -iS" to 30° C, was as follows: 

On October 'i (LS days) small, whitish delicate-fringed colonies ap- 
peared, just visible to the unaided eye. ( )n ( )ctober 11 ( 2o days), a distinct 
elevated stroma had formed, waxy and pale, with a vellow center contain- 
ing pycnidia with spores. Surrounding this was a white fringe of outgrow- 
ing mycelium. These stromata became 'l to (i millimeters in diameter, and 
closely resembled the stromata growing naturally on leaves bearing larvae 
(Plate III, Fig. 2()). Later cultures grown on the same medium bore 
stromata 25 millimeters in diameter, indicating that the size of any individual 
stroma depends on the amount of the medium taken, and the length of time 
before it is dried out (Plate III, Fig. 2T). The fungus was then transferred 
to test-tubes containing other media. Cultures were obtained on sterilized 
sweet potato, Irish potato, bread and rice. The most luxuriant growth was 
obtained on sweet potato plugs, this being ])robably due to the presence of 
sugar in that medium (Plate W . Figs. 2<S, -2!) and 30). 

The progress of the fungus on the various media was as follows : 

On sweet potato plugs, transferred from petri dish culture b}' inserting a 
platinum needle into a spore mass, there was no evident growth in three 
days. In six days, numerous small white points appeared along the scratch 
made by the needle. In fourteen days, stromata 2 mm. in diameter, and 
turning yellow, were formed. In twenty days these had become typical 



ASCHERSONIA FL.WO-CITRINA. 



19 



stromata with spores. In forty-seven days, these separate points had grown 
together into one waxy, yeUow mass, fringed and tipped with a wliite 
velvety growth of vegetative hyphae. as shown in the photograph (Plate IV, 
Figs. 28, 2!», .■)()). Xumerons pycnidial masses were also present. On 
Irish potato plugs, the growth of the fungus, for the first fourteen days, 
was ahout the same as on sweet potato plugs. From that time on, the 
growth was more feeble, and the yellow color rarely 
appeared. Typical spore-masses were not so abund- 
ant. On sterilized rice there appeared in ten days a 
slightlv yellow growth, not much raised above the 
surface. In eighteen days, the growth had spread 
out considerably over the surface of the rice, and the 
color had become a decided yellow, without present- 
ing any raised mass as described for sweet and Irish 
potatoes. In thirty-four days, there appeared small 
whitish patches over the surface of the yellow 
growth. On white cornmeal, the growth of the 
fungus was the same as on rice. ( )n bread, the 
fungus grew well and formed yellowish masses in 
a few weeks. 




FiR. 5. 

Hyphae of stroma. 

X 700. 




GERMINATION OF CONIDIA. 

The germination of the conidia of this fungus was very 
slow as compared with that of many fungi. In September, 
190(i, germination tests were made of conidia placed in 
hanging drops of distilled water, tap water, agar, and 
various solutions of glucose in water. These were pre- 

, , , . '^ , ^ . p , , . Fig. (). Conidia from 

pared bv placmg a number ot minute drops ot the solution dried pustules of 
on each sterilized cover glass, and putting in them by dinna, x looo. 
means of a sterile needle a few conidia from fresh pustules of the fungus. 
These were then placed in a moist chamber to keep them from drying out. 
In all of these solutions some germination took place. In distilled water and 
tap water, the germination was slow and feeble, the hyphal tube not advanc- 
ing far. The addition of sugar appeared to increase germination up to 10 
per cent, of sugar. Above lo per cent, germination was retarded, and at 30 
per cent. onl\- a few spores were seen to germinate. In ( )ctober, 1007, part 
of the same test was repeated with the same general results ; except that in 
this case the conidia in 5 per cent, glucose solution appeared to germinate 
a little more readily than in 10 per cent, and the conidia in 30 per cent, solu- 
tion refused to germinate at all. Parallel tests in part were made with 
conidia of Aschersonia alcyrodis with similar results. 

The table below gives the result of the tests for Aschersonia flavo-ciirina. 
In germinating, the first hyphal tube usually pushed out just behind one of 
the acute ends of the boat-shaped spore (Figs. 7, 8 and 9). The acute end, 



20 



FUNGI PARASITIC UPON ALKYRODKS CITRI. 



which seemed to lack protoplasm, was bent back in the opposite direction. 

The hyphal tube then grew very slowly, 
and in four days, in 10 per cent, glu- 
cose solution, began to form sporids 
at the distal ends (Figs. 8 and 9). 




Fig. 7. ronidium of Aschersonia flavo-citi-ina 
germinat'ng in :!0 per cent glucose solution 
after 27 davs. (a) Original conidiuni, (In 
spoie-libe bodies, x 1000. 




Fig. ». Kig. !'. 

rii>-8. 8-1). Conidia germinating. («) conidium. (b) 
liyphal tube, (c) sporid, X 1000. 



ASCHERSONIA FLAVO-CITRINA — GERMINATION OF CONIDIA. 



Medium. 


24 TO 28 HOURS. 


44 TO 48 


HOURS. 






Distilled water.. 


.! No germination. 


Germination 
ginning. 


just 


be- 




Tap water . , . 


• No germination. 


Germination 
ginning. 


just 


be- 


In 6' days good germ- 
ination, some hyphae 
2 or 3 times longer 
than the conidia. 



Glucose 1 per cent.i Germination just be- Fairly good germina- 
o-inning. tion. 



Glucose 2 per cent.' Germination just be- j (Dried out.) 
sinning. i 



Glucose 3 per cent.! Germination advanced | Very good germination 
I farther than in 2 per | of many conidia. 
cent, glucose. ! 



Glucose 5 per cent.! Good germination in 28 | Good germination, hy 
hours, hyphal tubes as j phae growing slowly. 
' long as conidia. 



Glucose 10 per cent.! Very good germination, 
hyphal tubes 2 to 3 times 
length of conidia. 



Very good germination, In 4 days sporids form- 
hyphae growing slowly, ing on ends of hyphaf 
tubes. 



Glucose 20 per cent. I Only a few just begin- Hyphal tubes as long as 
ning to germinate. conidia. 



Glucose 30 per cent.i No germination. 



No germination. 



A very few finally- 
germinated. S p o r ids. 
formed in 27 days. 



Germination tests of conidia from dried pustules luade at various times 
showed the following results : 

1. On November 10, 1900, hanging drop cultures were made from 
specimens sent in from Winter Park on September 28, 1906, which had 
remained in the laboratory exposed to the atmosphere for 4fi days. Tests. 



X'lvRTlCILLIUM HETlCROCr.ADUM. 21 

were made in distilled water, in tap water and in .") per cent. oRtcose cit a 
tempcratnre of l-")° to "^0° C. Xo germination occnrred np to December 
11, 190(i, when the slides were discarded. 

2. On Jannary ."), lilOT, hanging drop cultures of conidia in distilled 
water were made from leaves picked September 2S, liXKi, which had re- 
mained in the laboratory exposed to the atmosphere for ()8 days. Xo germ- 
ination was noticed up to January U, 1907. when the slides were discarded. 

o. On January 5, 1!)()7, hanging drop cultures in taj) water were made 
from leaves collected by E. W. Berger on December IS. I'JOG, and kept in 
the laboratory IS days. ( )n January 7, many conidia had germinated, and 
on Januar}- !l, some h}phal tubes were twice as long as the conidia. 

4. ( )n April IS, hanging drop cultures were made from leaves collected 
on September 28, ItMJii. at Orlando, and kept in the laboratory 203 days. 
No germination had occurred by April 29, 1907, when the slides were dis- 
carded. 

A SL'l'KK-rAKASlTlC Ol' ASCIIICKSOXJA J'LA\( t-ClTKl X A. 

A super-parasite Ixdonging to the genus Cladosjiorium has ])een noticed 
as of common occurrence on Asclicrsoiiia fhii o-citriua. Attention was first 
called to it b}" A. W. Morrill, who afterwards observed it at ( )rlando over- 
running this Aschersonia. in the summer of 19(l(i. Later on a Ijrief report 
was given 1\\' E. W. lierger. Plate VH, Fig. 4;!, shows a leaf from Or- 
lando with pustules of . Isclicrsojiia flavo-cifriiia covered over with the 
dark browji Cladosporiuni. This same fungus has also been observed by 
the writer associated with sootv mold ( Meliola ) in secretions of honevdew 
from Alcyrodcs citri, and it appears to aid at times in smothering the white- 
i\\ larvae, as does also the Meliola. Cultures of this fungus were readily 
obtained in •") per cent, glucose agar, and the fungus was transferred to 
potato plugs. The growth was rapid and the color was the same as on 
the leaves. 

DISTRinUTlOX ()!• ASCin':RS()NIA FLA\'0-CITRINA IN FLORIDA IN 1908: 

Altamonte Springs, 

Gainesville (introduced). 

Largo ( introduced ) , 

IMaitland, 

New Smyrna (introduced), 

Orlando, 

Oviedo, 

St. Petersburg (introduced). 

Winter Park. 

I\'. VERTICILLIUM HETEROCLADUiM PENZ. 

The attention of the writer was first called to this fungus ni November, 

1905, b} E. H. Sellards, Entomologist of the Florida Experiment Station, 

who brought in specimens of Brown fungus from Palmetto, Florida, with 

whici"! was associated a cinnamon-colored fungus. At the tnne of its dis- 



2:2 FUNGI PARASITIC UPON ALEYROUES CITRI. 

coverv on Aleyrodcs citri, it was thought that this fungus might possibly 
be tile spore-bearing stage of the sterile "Brown fungus" described by 
Webber, because of its close association with the stroma of the Brown 
fungus, and since it also resembled the Brown fungus somewhat in color. 
Cultures of the VcrticiUiiiin hctcrocladnm, however, together with inocula- 
tions of larvae of Aleyrodcs citri in the greenhouse, showed that this fungus 
was distinct from the Brown fungus found by Webber in ISiKi. Further 
evidence of its distinct character was subsequently obtained when it was 
found in other localities on Aleyrodcs citri and on other insects, in no way 
associated with the Brown fungus. At Palmetto, where it was first dis- 
covered, it was seen to be attacking the long scale, Mytilaspis citricola, that 
occurred on the same leaves with larvae of Aleyrodcs citri. In 1907 it was 
found on Mytilaspis i^loz'crii at Gainesville, quite independent of the Brown 
fungus. During the same year, it was found on a species of Diaspis on the 
leaves of Euonximis Aincriconns in the woods near Gainesville. Later on 
it was observed unaccompanied by Brown fungus on Alcyroaes citri at St. 
Petersburg, Fla. It was introduced by the writer on larvae of Aleyrodcs 
citri on a privet hedge at Gainesville in the fall of 1907. It was also intro- 
duced by Mr. Gaitskill along with the Brown fungus on larvae of Aleyrodcs 
citri at Mcintosh, during the summer of 1907. Specimens of the same 
fungus on Aleyrodcs citri were sent in from Apopka and Citra, Florida, 
early in 190S. In a few cases only has it been found in large quantities, 
and as yet its efficiency as a parasite of Aleyrodcs citri is not fully de- 
termined. In its parasitism it differs from the three fungi previously de- 
scribed, by attacking other insects not belonging to the genus Aleyrodcs. 
Several other species of the genus Verticillium have been reported as 
occurring on insects. J^erticilliiim aphidis Bauml.-'^ on plant lice, and Verti- 
cil liuiii jiiimitissiiiiuiii Corda-" on larvae of a small insect, were described 
from Europe. An undetermined species of Verticillium is reported by J. 
Parkin'"* on a scale insect Astcrolccaniuin iniliaris which was infesting the 
leaves of a bamboo bush in Ceylon. Parkin also refers to Gueguen as 
authority for the statement that Vcrticilliiini hctcrocladniii had been found 
in Africa and the xA.ntilles. It would therefore appear to be a widely 
distributed species. 

DESCRIPTION. 

This fungus was first described and figured by O. Penzig.-'^ in 1882, 
occurring on Lccauiuin hesperidnin on lemon leaves in Italv. His descrip- 
tion is as follows : 

J'rrticilliuin hctcrocladitJii Penzig (Fung. Agrumic. N. lOS. Fig. 1193). Hyphis 



"** Saccardo, P. A. Sylloge Fungorum, X, p. 546, 1892. 
■"Ibid. IV. p. 1.52, 1886. 

■-•"Annals Roy. Bot. Gard.. Peradeniya, Vol. Ill, Part I, p. 45, 1906. 
" Studi Botanici siigle Agrumi e sulle Planti Affini, p. 398, Tavola XLI, Fig. 3, Roma, 
1S87. 



\i-:KTlCII,IJU.M HirrF.ROCM.ADL'.M. 



23 



repentiljus, flongatis. [jaiiliuni ramosis, continuis ; rainis fertilil)us adscendentil)us, 
ramiilosis ; ramulis ternis \cl quaternis, oppositis vel altcrnis, patentibus, rectis, apice 
attenuatis ; conidiis in raniulorum apice solitariis, gcmiiiatis ve! ternis. saepius pedi- 
cellis brevissimis suffultis, i)1)li)ngis. h>"alini.s. .")..")-(; niicr. lung.. 2-:! niicr. crassis. 

J'crticilliiiiii licfcrocladinii. in general 
appearance, resembles the Urown fungus 
of Webber ( Plate l\\ Fig. ;;i). On close 
examination, however, it is found to be 
strikingh" different. The pustules, which 
are cinnamon colored, are powdery on 
the surface. L'nder the hand lens, they ap- 
pear brushlike in form, bristling with 
hyphae. From the edge of the pustules 
there grows out a creeping layer of white, 
delicate, interwoven hvphae. From these 
colorless hyi)hae, as well as from the top 
of the pustules, there arise upright con- 
idiophores. These may have either a 
simple series of whorls, 2 to 4 branches 
in each, or the branches of the whorls 
mav again Ije whorled The conidia are 
borne on the ends of the ultimate 

Fig.lO. Vn-tirilliiini hHn-iivlwhim. (rrl CunifllO- braUcheS ( Fi"". 10). 

V)hore with conidia I'ormins. X l.iO. (h) . ,\ , .... 

Conidiophore with mature conidia. X i.iu. The couidiophores are quite delicate, 

((■) Conidia, X 1000. , , , ,■ i-,v ^ .iwv • 1 

slender, hyaline, l.)(> to i\i) microns b}' 
o to 4 niicrons. several times septate. The conidia are oblong, hvaline. 
4 to (i microns long bv 1.-") to 2.5 thick. The main body of the cinnaivion- 
colored stroma when mature becomes powder\- in I^ 

appearance, and under the microscope it is found ^^sT^ 
that the hyphae have broken up into short i)ieces 
irregular in shape and length with rounded ends, 
some of them quite closely imitating spores ( Fig. 
11). These have thicker walls than the conidia. 
and probablv act as reproductive bodies in carry- 
ing the fungus thrt^ugh a |)eriod of dry weather. 





Fig. 11. Short iiyphel bodies 
intowliieh the central por- 
tion of a mature pustule 
breaks uj). X l.iO. 



CULTURES. 

Pure cultures of this fungus were made in Xovember, 190,"), soon after 
the fungus was discovered on Alcwodcs citri. The next year other cultures 
were made and spores of the fungus transferred from cultures to larvae 
of Akyrodcs citri in the greenhouse. The fungus was readily grown in 5 
per cent, glucose agar by drawing a moistened platinum needle over the 
top of the upright couidiophores and then washing it off into the melted 
agar. 

On November 12, 19()(i, two petri dishes (A and ?> ) of .") per cent, glu- 



24 FUNGI PARASITIC UPON ALRYRODES CITRI. 

cose agar were poured. A moistened needle was drawn over the upright 
brush of conidiophores and washed into a httle bouillon in a test-tube. In- 
oculations were made from this with a platinum loop, nine loops being 
transferred to A, and nine from A to B. 

On November 30 (8 days), 130 pure white mycelia appeared in A and -i 
in B, 3 to 4 mm. in diameter, with reddish brown center and a brush of up- 
ward growing white conidiophores. On December 5 (33 days), the mycelia 
in B were 25 mm. in diameter and reddish brown. On December 12 (32 
days), the mycelia in B were 30 to 35 mm., and cinnamon-colored almost 
to the edges. By this time a pustule was formed composed of closely inter- 
woven hyphae and closely resembling the pustules upon larvae of AJcyrodes 
citri (Plate V, Fig. 34)! ' 

The fungus was transferred to test-tubes of sterilized Irish potato, 
sweet potato, rice, white cornmeal, stems of canna and of caladium, and 
bread ; on all of which the fungus grew to some extent. It grew best, how- 
ever, on sweet potato and bread, over the entire surface of which it formed 
a felted cinnamon-colored stroma (Plate V, Figs, 32, 33). On rice the 
color was that of ocher, and on caladium stems it was brick-red. On the 
other media the color was nearly that of the growth on 5 per cent, glucose 
agar. 

The growth on sweet potato plugs was recorded as follows : On Novem- 
ber 23, 190G, conidia from cultures made November 13, were rubbed on the 
surface of the potato. On December 5 (13 days), a brown colored growth 
had formed over the surface of potato. By December 13 (30 days), the 
entire surface was yellowish brown. On January 15, 1907 (39 days), the 
entire surface was covered over with a thick cinnamon-colored mat of 
fungus. 

GERMINATION OF CONIDIA. 

Conidia were placed in distilled water in hanging drops. It was found 
that they germinated much more rapidly than did the conidia of Ascher- 
sonia. In distilled water, in 34 hours, conidia had just begun to elongate; 
in 48 hours a few spores were found with short hyphal tubes. In bouillon, 
in 34 hours a slight germination took place, the hyphal tubes becoming as. 
long as the spore ; in 3 days, the hyphae were 130 to 300 microns long and 
1 to iy2 microns wide, and branched once or twice. 

In 5 per cent, glucose, in 34 hours, the tube had extended one to two- 
times the length of the spore, and in three days, the growth had proceeded 
farther than those in distilled water. 

When germinating, the spores first swelled, elongated, and then sent out 
a hyphal tube from one or both ends. 

INFECTION OF LARVAE OF AtEYRODES CITRI. 

On December (5, 190(5, small badly infested orange trees which had pre- 
viously been in the greenhouse, were covered with large bell jars. Conidia. 
from a petri dish culture poured November 13, 1906 (24 days old), were 
shaken up in sterile water, and this was sprayed on to the plants with a 
small atomizer. In 35 days several leaves were found with stromata in a 
spore-bearing condition, identical with those from which the culture had 
originally been obtained. These had evidently developed sooner than 35 
days, and had been overlooked. They became powdery in appearance, and 
in all particulars were like the natural pustules. 



SPHAEROSTILBE COCCOPHILA. :^0 

On September 19, 190T, leaves containing J'crticilliiun hctcrocladuui 
were tied to a twig of privet {Ligustrnm ovalifoluim) bearing abundant 
larvae of Aleyrodes cifri. The weather was moist for two weeks after. 

On October 5 (16 days), pustules were very evident on many larvae 
on leaves adjacent to those tiecl in. L'nder the microscope a mycelium was 
to be seen inside the larvae. On October 25 (3() days), the fungus with 
conidia was well established on a few neighboring leaves, but was not 
spreading rapidly (Plate V, Fig. 35). 

On November 16, leaves of Enonyiiiiis Aiiicricaiiits bearing a species 
of Diaspis attacked by rcrficllliiim hctcrocladum were pinned on to an 
orange tree at Gainesville by E. \V. Berger. On December 31, 1907, three 
pustules of freshly grown Verticillium were found (one on a scale insect, 
probably Lecanium, and the others apparently on larvae of Aleyrodes cifri). 
on a tree next to the one in wdiich the fungus had been pinned. 

INSECTS PARASITIZED, WITH LOCALITIES. 

Aleyrodes cifri: Palmetto, IManatee. St. Petersburg, Gainesville, Apopka. 
Citra, Mcintosh. 

Myfilaspis gloz'crii: Gainesville. 

Diaspis sp. on leaves of Bnonynuis Ainericainis: Gainesville. 

Lecanium sp. on orange leaves: Gainesville. 

Lccaniiiin hcsperidiiin on lemon leaves: Italy. 

Myfilaspis cifricola : Palmetto, Citra. 

In Africa and the Antilles the host insect is not known. 

\'. SPHAERC )STILBE COCCOPHILA TUL. 

This fungus, which has a world-wide distribution, and has been re- 
ported as a parasite on no less than fifteen dififerent species of scale insects, 
has been found in a few instances attacking larvae of Aleyrodes cifri. 

The conidial stage of this fungus (Figs. 14 ^ 
and 15) was discovered by Desmazieres-'- on 
scales of a coccid on }Oung wiliow-stems in 
France, as early as 184S. It was described un- 
der the name Microcera coccophiia. The per- 
ithecia (Figs, l'^ and 13) were discovered by 
Tulasne-- and described b}- him in 1865 as oc- 
curring on scale insects on species of Laurus. 
^%2;e^Xi:!^na Salix and Fraxinus in France, Italv and Amer- J]^-^^ 
.showing asci Within, j^^. Desmazieres' description is as follows: " .'■^'■»^^?,„ 

■^ '^- ^ cnim.X20o. 

Microcera, Desmaz. Velum externum persistens. membranaceo-floccosum, dein 
supra in lacinias plures rumpens; receptaculum clavatum carnosum e fibris sub- 
simplicibus sporidiiferis formatum ; sporidia fusiformia, acuata. 

Microcera coccophiia Desmaz. M. minutissima, subcaespitosa cornuto-conica, 
simplex, lateritio-rosea, basi membrana tenuissima albida vaginato-connata. Sporidiis 
paucis, hyalinis, elongatis, utrinque acutis. Hab. in coccis. Hieme. 

^^ Desmazieres. Ann. des Sc Nat., Tome X, p. 359, 1848. 
'^Tulasne. Carpologia, Vol. Ill, 105, 1865. 




26 



FUNGI PARASITIC UPON ALEVRtJDES CITKI. 



The ascus stage is described in Saccardo's Sylloge Fungorum-'"' thus : 
S fhacrostilbc coccofliiUi Tul. Carp. III., 10.5. — Peritheciis permultis supra et prope 
stromata conidiophora nascentibus, minimis globosis, obtusis, brevissime papillatis, 
glaberrimis, nitide rubris. saepe 4-5 sociatis, senio collabentibus ; ascis linearibus, 
60-80X6^; sporidiis oblique monostichis, ovatis, lOX^, I-septatis, subhyalinis, leniter 
constrictis. — Stat, conid. Microcera coccophila Desm. Stromate e crusta coccorum 
solitarie oriundo. crasse teretiusculo, obtuso, rubro 2 mi'l. alt. : conidiis lineari- 
lanceolatis 4-6 locularibus, 65X6 subhyalinis. 

In 1893, Ellis and Everhart''"' in "North American Pyrenomycetes" gave 
nearly the same description in English, and reported this fungus on a speci- 
men of Alnns scrnilata collected in Pennsylvania, adding: 

The conidial stage (Microcera coccophila Dcsjii.) which has been, sent from 
Florida by Dr. Martin and collected in Carolina by Ravenel (F. Am. 286), has stroma 
arising from various species of dead bark-lice. It is red, obtuse and about 2 mm. 
high. The conidia are linear lanceolate, 5-7 septate and 56-65X5-6 microns, nearly 
hyaline. 

D. McAlpine-'" in describing the con- 
idial stage of this species in Australia 
gives the measurements of the conidia 
as 75— 108X5>4— 81-4 microns. Meas- 
urements made of a number of Florida 
specimens from different localities gave 
70— 112X3.5— (i microns. 

of the perfect stage from Florida specimens were as 
follows: — Perithecia 350 — 300 long by 300 microns 
thick. Divisions of perithecial wall 6 — 10 microns, 
Asci, 70—98X8—12 microns. Spores 12— 18 X'^— 9 
microns. 

HISTORY. 





Fig. 15. Conidia, 

Aleasurements x 200. 



Fig. 14. Sporodochium, or 

conidial fructification of 

Sphaerostilbe coccophila, 

X 75. 



This fungus has been found in nearly every coun- 
try in the world. In 1892, M. C. Cooke'-'^ spoke of it 
as common in Europe and as a well-known parasite on dead Coccus. In 
the same year it was reported from Jamaica by T. D. A. Cockerell.-''^ In 
1894:, Henry Tryon"*-' reported it on the long scale, the red scale and the 
circular black scale in Queensland, Australia. In 1897, it was reported 
by P. H. Rolfs^" as a parasite of the San Jose Scale, Aspidiotits pcniiciosiis 
Comst. In 1899, it was reported by D. McAlpine^^ on Aspidiofiis ourantii 



^* Saccardo. Sylloge Fungorum, II, p. 51.3. 188;i 

^" Ellis, J. B. and Everhart, M. B. North American Pyrenomycetes, p. Ill, 1892. 
^^ Fungus diseases of Citrus Trees in Australia, Dept. of Agr., Victoria, p. 113, 1899. 
"Vegetable Wasps and Plant Worms, p. 322, London, 1S92. 
^* Bui. Botanical Dept. of Jamaica, No. 36, p. 6, 1892. 
^"Queensland Dept. of Agr., Bui. 4, p. 15. 
'"A Disease of San Jose Scale, Fla. Exp. Sta. Bui. 41. 

" Fungus Diseases of Citrus Trees in Australia, Dept. of Agr., Queensland, pp. 27 and 
28, 1899. 



SPHAKROSTILBE COCCOPHILA. 37 

:\Iask. in Australia. In 1 !)()(). P. H. Rolfs^- reported that Mytilaspis citri- 
cola Pack.. Myfilaspis gloirrii Pack., and Parlatoria pcrgandii Comst. were 
all attacked by this functus in Florida. The same year F. S. Earle^^ found 
it common on Asf^idiotiis obsciirus Comst. on water oaks in Alabama. It 
also occurs naturally in Georgia, and has been found as far north as Phila- 
delphia, Pa. In 1!)01, Fuller-*^ reported finding the same fungus in Natal, 
South Africa. In 1J)();5, H. A. Gossard^'' first reported its occurrence on Al- 
cvrodcs cifri. In 190;5, F. S. Earle^" found it in Porto Rico, and in 1904^^ 
in Cuba : in both places on Mytilaspis citricola. In 1904, S. I. Kuwana^'^ 
reported the fungus as present upon Asp idiot us pcniiciosiis Comst. and on 
Diaspis pciifagoiia Targ. in Japan. He spoke of finding it on the last- 
named insect in the mountain districts. In 19;)(i, it was reported bv J. 
Parkin-^-' as occurring upon Mytilast'is citricola Pack, and Aspidiotiis aiir- 
antii ]\[ask. in Ceylon. In 190S. it was reported by C. W. Howard'"^" from 
the Transvaal. It has also been found by E. W. Berger on Aspidiofiis 
hcdcrac (\'all) and Aspidiotiis aiicylits Putnam, in Florida. 

Both the conidial and ascus stage of this fungus ( Plate \l. Figs. ;i(i. 
:)T, oS ) are found commonh- in Florida, although the latter is not at all 
common in other ])arts of the world. In Ceylon, the perithecia have not 
been found bv Parkin; and one would infer, from the name ]\Iicrocera, 
which is used ])y I). Mc Alpine, that the perfect stage is not common in 
Australia. 

RELATION OF S. COCCOPHILA TO THE SAX JOSE AND OTHER SCALE INSECTS. 

The use of this fungus as a practical remedy in combating the San Jose 
scale was first brought out by P. H. Rolfs in 1S97, in Bulletin 41 of the 
Florida Experiment Station. This fungus was discovered bv him upon the 
San Jose scale in northern Florida during the previous year. By means of 
pure cultures and infection experiments, Rolfs demonstrated that the San 
Jose scale could be readily infected with spores of this fungus grown upon 
sterilized bread or other media. The results of these experiments are given 
in the bulletin referred to. 

This fungus was also discovered to be a common parasite of the obscure 
scale. Aspidiotiis obscunts Comst., on the twigs of water oaks (Oticrcits 
aqnatica). A simple method of infection has been developed in Florida by 
one of the peach-growers, Mr. F. P. Henderson, by tying into the top of 



*- Proc. Fla. Sta. Hort. Soc, p. 6.5, 1900. 

'^'Ala. Exp. Sta. Bui. 106, p. 198, 1900. 

'"First Rept. of Govt. Entomologist, Dept. of Agr.. Natal, p. 99. 1901. 

'-'Fla. Exp. Sta. Bill. 67. p. 623, 190:!. 

'"Annual Rept. Office of Exp. Sta.. Washington. D. C. p. 4.-)7. 1903. 

■■^Primer Informe Annual de la Estacion Central Agronomica de Cuba (1904-0.5), 

p. 162, 1906. 
'"Japan Imperial Agr. Exp. Sta. Rept., p. 26. 1904. 
'■'.Annals Roy. Bot. Card., Peradeniya, Vol. III. Part I, p. .50. 
■"■"Dept. of Agr., Transvaal. Agr. Journal, p. 6. 1908. 



*^8 FUNGI PARASITIC UPON ALEYRODES CITRI. 

an infested tree a short piece of wood whose bark bears a good supply of 
the fungus. This has proved to be a very effective way of distributing this 
fungus, and has already saved thousands of dollars to the peach and orange 
growers of the State. In addition to attacking Aspidiotus perniciosus and 
Aspidiofits obsciinis, this fungus is efifective in checking a number of other 
scale insects in Florida. It is, under favorable moisture conditions, an 
effectual parasite of Mytilaspis citricola, Mytilaspis gloverii, Aspidiotus 
fiais, Aspidiotus hcdcrac and Parlotoria pergandii. There are times, in dry 
weather, when these scale insects get ahead of the fungus ; but a moist 
period of a few days will quite often enable the fungus to kill them off 
almost completely. (Plate \I, Figs. 36, 37 and 38.) 

The effective work of this fungus, and two others, O phioiicctria coc- 
cicola E. & E., and Myriaiigiiim diiriaci Mont, upon the orange scales, is 
readily shown by spraying an orange tree very thoroughly with Bordeaux 
mixture. During the summer and fall of 1907, the author sprayed a num- 
ber of orange trees with Bordeaux mixture for another purpose. The trees 
were sprayed very thoroughly, once in May, once in July, and once in 
September. Before the first spraying, the trees were practically unhurt by 
Mytilaspis citricola, only a few individuals of this scale being found on any 
part of the trees. After the first spraying this scale insect began to spread, 
and increased slowly in numbers until November, when the trees were badly 
attacked by the scale. Other trees near by, that had received no spray, were 
as free from scale as at the first. The fungicide had evidently destroyed, 
on the sprayed trees, the fungi that had been all along working upon the 
tmsprayed trees. 

Soon after the discovery of this fungus in Florida by P. H. Rolfs, ex- 
periments were made by S. A. Forbes-^ ^ of the Illinois Experiment Station, 
B. Smith'5- Qf ^|-^g >\Te^y Jersey Experiment Station. J. Craig-^-^ of the 
Canadian Experiment Station, and F. M. Webster''-^ of the Ohio Experi- 
ment Station, to introduce SpJiaerostilhe coccophila on San Jose scale in 
the North, but the climate of these States did not prove to be conducive 
to its spread, and the work was abandoned. 

S. COCCOPHILA AS A PARASITE OF ALEYRODES CITRI. 

As was stated previously, Sphacrostilhc coccophila seems to have been 
first reported as parasitic on Alcyrodes citri in 1903 by H. A. Gossard. It 
was found on larvae of Alcyrodes citri on orange leaves received from Or- 
lando. In 1905, E. H. Sellards'"*-^ also reported having received it from 



''111. Exp. Sta. Bui. 56. pp. 270-280. 

'"'N. J. Exp. Sta. Rept. 18, pp. 470-479, 1897. Rept. 19, pp. 445-446, 1898. Rept. 24, p. 

567, 1903. 
'"^ Canada Exp. Farm Rept., p. 119, 1897. 
"^^Ohio Exp. Sta. Bui. 103, p. 198, 1898. 
='Fla. Exp. Sta. Rept, p. 27, 1905. 



illCROCRRA. 



29 



Orlando. In 1906, E. W. Berger found it on a few whitefly larvae at 
Leesburg. Florida. 

The effect of this parasite upon Alcxrodcs cifri seems to be of little 
practical value. It has only rarely been observed attacking this insect, and 
then does not occur in quantity, as do the other fungi before spoken of. It 
is not uncommon to find a large amount of this fungus upon Mytilaspis 
citricola in trees that are at the same time infested with larvae of Alcyrodcs 
cifri on which no fimgus can be found. 

LIST OF INSECTS PARASlTIZlvD. 

A list of insects reported to be attacked b}' this fungus is here given, 
together with the authority for the report and the localities in which they 
were found parasitized : 



Name of Insect. 


Locality. 


Authority. 


Alcvrodcs cifri R. & H 


Florida 


H A Gossard 


Aspidiotus aiicvlns Putnam 


Florida 


E W. Berger. 


Aspidiotus articiilatus Morgan 


Jamaica 


T D A. Cockerell. 


Aspidiotus articiilatus Morgan 

Aspidiotus articulatus Morgan 


West Africa 

West Indies 


I. Parkin, 
j. Parkin. 
D. McAlpine. 
Fuller. 


Aspidiotus aurantii Mask 


Australia 


Aspidiotus aurantii Mask 


Natal 


Aspidiotus aurantii Mask 


Cevlon 


J. Parkin. 

C W. Howard. 


(Chrvsoiiiplmlus) aurantii Mask 


Transvaal 


Aspidiotus ficus Comst 


Florida 




{Ch.rxsomphalus aoniduiii) Linn 


Transvaal 


C W. Howard. 


Aspidiotus hcdcrac (Vail) 


Florida 


E W. Berger 


Aspidiotus obscurus Comst 


Florida 


P H Rolfs. 


Aspidiotus pcrniciosus Comst 


Florida 


P. H. Rolfs. 


Aspidiotus pcrniciosus Comst 


Taoan 


S. I. Kuwana. 


C/i'onaspis citri Comst 

Diaspis pcntagona Targ 

Fiorinia fioriuiac Targ 


Cuba 


Cook and Home. 


Tapan 

Mauritius 


S. I. Kuwana. 
J. Parkin. 
J. Parkin. 
J. Parkin. 

F. S. Earle. 
F. S. Earle. 
P H. Rolfs. 


Isclinaspis Uliforniis 


West Indies . . 


Mytilaspis citricola Pack 

Mytilaspis citricola Pack 

Mytilaspis citricola Pack 

Mytilaspis citricola Pack 

Mytilaspis glovcrii Pack 

(Lcpidosophcs) gloi'crii Pack 

Parlatoria pcrgandii Comstock 


Cevlon 


Cuba 

Porto Rico 

Florida 


Florida 




Transvaal 

Florida 


C. W. Howard. 
P. H. Rolfs. 



VI. MICROCERA SP. 

Microccra sp. : Mycelium pure white: hyphae delicate, septate, loosely 
branching, hyaline. -1 — ^) microns thick ; conidia at first borne on the ends 
of the branches, one and two-celled, oval to oblong, 7 — 12X3 microns; 
conidial tubercules various in size, cushion-shaped, pink, made up of a 
compact mass of conidia ; conidia lunate, acute at both ends. 3 to 5 septate, 
mostly 28 — 40X3.5 — .-) microns. A few conidia reach 52 microns. On 
Alcvrodcs cifri R. & H., on citrus trees in Florida, V. S. A. 



30 



l-UNC.l I'AKASITIC lU'ON ALKVRODl^S CITRI. 



ci:? 




DISCOVERY. 

In September, IWl , Prof. P. H. Rolfs, when visiting the orange grove 
of Mr. F. Wills at Sutherland, Florida, noticed that a great many larvae 
of Alcyrodcs citri were dead or dying. None of the known parasitic fungi 
were to be seen, but b}- the use of the hand lens a whitish fringe could be 
noticed growing from the edges of the larvae. Specimen leaves were 
brought back to the laboratory on September 13 , and on microscopic ex- 
amination, the larvae upon these leaves were found to be diseased by a 
species of Microcera. Leaves sent in b)- Mr. Wills on September 3(5, were 
found to have even more abundant fungus, and nearly all the larvae were 
dead. Orange leaves sent in from Manatee a few days later were also 
found to bear larvae infected with the same fungus. This Microcera has 
since been found at Largo, Bayview, and Safety Harbor by the author, and 
has been brought in from Orlando, DeLand and Leesburg b>' E. W". Berger. 
A preliminary notice of this fungus was published by 
the author in Press Bulletin G8 of the Florida Experiment 
Station, "A Xew Whitefly Fungus". This fungus presents 
a fringe of delicate white hyphae growing outward from 
the edges of the larvae (Plate VL Fig. 41). These hyphae 
at first bear one-, two-, or three-celled conidia, which are 
oval to fusiform in shape (Fig. Ki). Afterwards there are 
formed on the edge of the larvae 
pinkish spore-masses, which are 
made up of a compact mass of lunate 
spores (Fig. 17). These are '^- to 
38 to 40 microns long, by 3..") to •") 
microns thick, in fresh specimens. Wlien the larvae 
are placed in distilled water on a microscope slide, 
the fungus spores are seen to float apart and spread 
out in the water. 

CULTUKKS. 

Culture of this Microcera were grown much more easily and quickly 
than those of any of the previously described fungi. This fungus grew 
rapidly on nearly all kinds of media which were tried. 

On September 14, 11)07, the day after the fungus had 
been examined and recognized as a new parasite on Aley- 
rodcs citri. three sets of petri dish cultures of three each. 
A, l^ and C, were prepared according to the i:sual method 
for isolation. The first set was made by touching an in- 
fected larva with a moist platinum needle, and washing 
the needle ofif in test-tube A. \\ received three loops from 
A, and C three loops from H. Tn three days on petri dish 
A, two mycelia and a nivmber of bacterial colonies were 
evident. Tn nine days, the fimgus had overrun almost the 
entire dish, in s\)\ie of the bacteria present, and was pro- 
ducing an aliundance of conidia. B and C developed no fungus. 



Fig. IG. Hyplia of 
Microcera from 
edge of larva 
sliovving branch- 
ing and forma- 
tion of one- and 
two-celled coni- 
dia. X 1000. 

•Vseptate, and 




<3;.7?k 



Fig. 17. Conidia of Microcera 
from larvae dried on leave.s 
of Citrus. X 450. 




Fig. l.s. Conidia 
from test-tnbe ful- 
ture of Microcera 
on bread, X 1.50, 
(Culture had dried 
out.) 



MICKOCKRA. 31 

The second set was inoculated with spores from a test-tube in which 
an infected larva had been shaken up in water. In both A and B, a good 
growth of fungus appeared. The fungus just showed after 24 hours. In 
A, in three days, there w'ere about oO mycelia. In I'), in three days, the 
mycelia, three in number, had become 10 to 12 mm. in diameter, loosely 
tufted, with numerous conidia on the upwardly projecting, irregularly 
branching hyphae. In nine days, the growth had covered the entire surface 
of the medium. 

The third set was inoculated from a test-tube containing a little sterile 
water, in which two infected larvae had been placed. Only the first petri 
dish A develo]:)ed a growth of Microcera, which grew as described for the 
second set. 

The fungus in all cases was of a pure white color. It grew in loose 
tufts, with u])wardly growing, very delicate hyphae, forming a loose, fluffy 
mass, which soon collapsed when the cover of the petri dish was removed. 
A microscopic examination of this growth showed that it was made up of 
irregularly branching hyphae bearing conidia. 

All intermediate shapes of spores from the oval one-celled conidium, 
to the septate lunate conidium, could be found in the same culture. (Figs. 
1(). 17, IS). It may l)e remarked in this connection, that in the cultures of 
Sphacrostilbc coccophila made bv P. H. Rolfs in 1S!I7, the conidial stage 
of which has been referred to Microcera, these one- and two-celled coniflia 
appeared, and are figured by him in Bulletin 41 of the Florida Experiment 
Station, Plate II. Judging from the growth of Microcera sp. in cultures, 
it would probably fit into the genus Fusarium, but since the distinction be- 
tween Microcera and Fusarium is rather vague, we prefer to hold to the 
name Microcera until the perfect stage is worked out. Perithecia of this 
fungus appear to be developing at the present time on culture media. 

On September 18, two test-tubes of standard agar, one of Irish ])otato, 
and one of rice, were inoculated by drawing a moist needle over the top 
of culture B of the second set poured on September 14. On agar tubes 
there seemed to be some evidence of growth in three or four hours. ( )n 
September 21 (3 days), tufts of white mycelium were formed over the 
entire surface. ( )n November 20, the agar had begun to shrink away from 
the sides of the tube, and the fungus had grown down over the sides of 
the medium. On Irish potato. September 28, almost the entire surface was 
covered with a snowy white growth of fungus. On rice in a oO cc. flask, 
bv November 11 ( o4 days) the entire surface was covered with growth, 
and the spaces between the rice grains were packed with a fungus mycelium. 
The mycelium was very thick, matted, and pink on the sides near the glass 
(Plate' VI, Figs. 30 and 40). 

On September 2.i, a test-tub.e and a flask of rice, and two tubes of bread, 
were inoculated from the same culture as before, (^n rice, September 28 
(3 days), a delicate growth 10 mm. high was formed in the test-tube. The 
rice had turned pinkish from the top to ^4 inch down on the sides. In the 
flask almost the entire surface was covered, and was pinkish at the base on 
the sides of the rice. By October 18 (23 days) the fungus had grown 
through all the availaljle spaces in the medium, forming a pinkish matted 



32 FUNGI I'AKASITIC UPON M.KYKODES CITRI. 

growth. Un November 11, numerous conidia were present in pink masses 
on the sides of the rice. On the bread, on September 28 (5 days), a delicate 
white growth was formed over the upper surface. On October 10 (15 
days), the growth had taken up every available space in the pores of the 
bread, giving it a pinkish matted appearance. 

On October 11 the following cultures were made by transferring spores 
from the bread cultures of Sep"tember 25, which had been transferred once 
before. Three tubes of agar, one of sweet potato, one of Irish potato, one 
of rice in a 50 cc. flask, and one of bread were used. Notes were taken on 
October ID only. In the three agar tubes, which reacted l.<». 1.5 and 2.0 
respectivelv to phenolphthalein, the growth was about one inch high with 
abundance' of conidia. There was no noticeable difference in the growth. 
On sweet potatoes, a pure white, delicate growth appeared ; on Irish po- 
tatoes, a very abundant growth ; on rice, an abundant growth with a pink- 
ish color on the surface, and thick mycelium between the rice grains. 

IXFKCTION OF ALKVKODKS CITKI. 

On September 1!». 1!)07. infection experiments were made on healthy 
whitefly larvae from cultures of this fungus. The larvae were on the leaves 
of a privet hedge (Lignstnim ovalifoUum) in Gainesville. The following 
is taken from notes made at the time of the experiments : 

Healthy larvae were very abundant on the privet leaves. The w^eather 
was damp after a rain. Inoculations were made from 3 to 5 r. m. 

No. 1. Inoculation was made from culture of September l-t ; conidia 
were penciled on the under side of the leaves on one branch with a moist 
camel's-hair brush ; a piece of cheese cloth was tied around the inoculated 
branch. On September 21 no conidia were found ; the cheese cloth was 
removed. On September 28. no conidia were found. On October 5, abund- 
ant conidia of Microcera were present. On October 25, about 50 per cent, 
of the larvae were dead. 

No. 2. Inoculation was made from same culture, penciled on as in No. 
1, but not covered wath cheese cloth. On September 28, no spores were 
found. On October 1, spores of Microcera were present. On October 5, 
pink spore-masses were developed on the edges of larvae. By October 25, 
about 50 per cent, of larvae were dead. 

No. 3. Conidia were penciled on as above, and not covered with cheese 
cloth. On September 21. no spores were found. On September 28, no 
spores were found. On October 1, Microcera spores were present. On 
October 5. pink spore masses were present on the edges of the larvae. On 
October 25, about 50 per cent, of the larvae were dead. 

No. 4. Inoculation was made from larvae on citrus leaves from Mana- 
tee. No cheese cloth was tied around. On September 21, larvae seemed to 
be attacked by a small fungus, which looked like the Microcera of the 
cultures. The conidia were one- and two-celled. On September 28. abund- 
ant spores of Microcera on dead larvae were found, and live larvae with 
filaments of fungus within. About 60 per cent, estimated dead. On Octo- 
ber 5, pink conidial masses were evident on edges of larvae. 

No. 5. A branch as a check was not inoculated, but tied up with cheese 
cloth. On September 21. no conidia of Microcera were to be found. On 
September 28, no conidia of Microcera to be found. 



microci:ka. 33 

No. G. A branch near Xo. 5 was neither inoculated, nor tied with cheese 
cloth. On September 21, no spores of Microcera were to be found. On 
September 28, no spores of Microcera were found. 

No. 7. A branch above No. 4 was neither inoculated, nor tied with 
cheese cloth. When examined on September 28, no Microcera could be 
found. 

During the first two weeks after these infection experiments were made 
there were frequent rains, and the weather was quite moist. This was fol- 
lowed by two weeks of drier weather during which the fungus apparently 
ceased to grow. These inoculation experiments show that under favorable 
climatic conditions like those under which they were carried on, the larvae 
of Aleyrodes citri may readily be infected either directly from previously 
infected larvae, or from pure cultures. 

CERMINATIOX OF COXUIIA. 

The conidia of Microcera germinated quite readily in water. On Octo- 
ber 3, a hanging drop culture was made w'ith conidia from a potato culture. 
In 24 hours, one of the cells of the conidia, usually the end cell, sent out 
hyphal tubes to a distance of one to four times the length of the conidia. 
On the end of a number of these were seen small oval sporids (Fig. 19). 
In 48 hours the hyphae w^ere 6 to 7 times the length of the conidia, some 
of them branched as in Fig. 19. and many sporids had formed. In six 
days the branching hyphae were 
prominent, with many sporids. The 
segments of the conidia had become 
swollen, thus causing constrictions 

, '^ Fig. lU. C'ODidiumof Mipiocera germinatlna: 

at the septa. and forming sporids. r^) Conidiuiii.('i)hyphal 

tube, (t) sporid, X 150. 

VARIATION IN SIZE OF CONIDIA. 

The measurements of conidia at various times and under various con- 
ditions indicated a considerable variation in size. The greatest variation 
was in the length. As has been said, the conidia varied from oval one- 
celled spores to long lunate spores. Measurements of lunate spores on 
larvae were as follows : 

On September 23, the first specimen from Sutherland after drying bore 
conidia measuring 28 — 10 by 3.5 — 5 microns. On September 20, the second 
lot of specimens from Sutherland, while still fresh, contained conidia meas- 
uring 36 — 45X3.5 — 1.5 microns. On October 5, privet leaves from inocu- 
lation experiment No. 4. at Gainesville, while still fresh, bore conidia meas- 
uring 31—52X3.5—4.5. 

Measurements of lunate spores in cultures were as follows : 

On September IT, conidia from cultures made September 14 measured 
21 — -32X3.5 — 4.5 microns. On November 21, conidia from culture on 
potato, measured 12 to 30 microns long ; two-celled conidia were 12 microns, 
the others longer. On February 2, 1908, from cultures 101 days old, made 
October 26, 1907, on white cornmeal cultures not dried out: conidia in pink 




34 FUNGI PARASITIC UPON ALEYRODES CITRI. 

cushion-shaped masses, 5-septate, -iO — 60 microns long ; most of them 40 
microns, few 60 microns. On June 2, 1908. from culture on bread made 
September 25, li)06, dried out; conidia 15 — 30X3 — 4.5 microns. 

DISTRIBUTION Ol' MICROCEKA SP. IN FLORIDA. 

Sutlierland September 13, 1907. 

Manatee September IS, 1907. 

Gainesville September 31, 1907. (Introduced.) 

Leesburg October 11, 1907. 

Orlando November 25, 1907. 

Largo November 1907. 

Titiisville December 3, 1907. 

Safety Harbor March, 1908. 

VII. THE BROWN FUNGUS OF ALEYRODES CITRI. 

In Alarch, 1896, H. J. Webber'^*' discovered this fungus on whitefly 
larvae in the grove of J. H. Viser. Manatee, Florida. During the summer 
of that year the fungus spread rapidly through the \'iser grove, and was 
observed to be a very efifective parasite of Alcyrodcs citri. As no fructifica- 
tion of any kind has been found in connection with this fungus, it has not 
been classified. It has been known since its discovery as the "Brown 
Fungus" of the whitefly (Plate MI, Fig. 42). 

DESCRIPTION. 

Webber"'' gave a general description of this fungus in Bulletin 13 of 
the Division of Vegetable Physiology and Pathology, as follows : 

The mature stroma is compressed hemispherical, frequently having a slight de- 
pression in the apex over the center of the insect, where the hyphae come together as 
they spread from the edges of the scale in their development. The size varies greatly, 
according to the stage of development of the insect attacked. In very young larvae 
it is from I4 to Yz a millimeter in diameter. In mature larvae and pupae it frequently 
reaches 2 millimeters in diameter. The thickness, or height, also varies in like manner, 
specimens on mature larvae or pupae being usually from 17.") to 260 microns, while 
those on young larvae are nuich thinner. * * - The stroma is commonly seal 
brown, with a shade of chestnut, but becomes slightly darker with age. * * * The 
hyphae, which make up the body of the stroma, are light brown, very tortuous, and 
but slightly branched. Those in the body of the insect are of similar character, but a 
much darker brown. From the base of the stroma a ground mycelium, or hypothallus, 
spreads out in all directions on the surface of the leaf, forming a compact membrane 
near the stroma, but becoming gradually dispersed into separate filaments. * * * 
The hyphae of the h.vpothallus are colorless, sparingly branched, mostly continuous, 
having only an occasional septum, and are from 5 to 7 microns in diameter. In some 
places in the hypothallus, where the hyphae are apparently somewhat massed and 
knotted, they become light brown, similar in color to the isolated hyphae of the 
stroma. 



'"Div. of Veg. Phvs. & Path., Washington, D. C, Bui. 13, p. 27, 189^ 
"' Ibid. pp. 28-30. 



THE BROWN FUNGUS. 35 

BROWN FUNGUS OF PARKIN. 

J. Parkin-"''' in writing" of the Ceylon forms of fungi parasitic on Aley- 
rodes, mentions having found on three different kinds of leaves a hrown 
sterile fungus, which he thinks is similar to the one descrihed by Webber 
on Alcyrodcs citri. He also states that these brown pustules were in many 
cases closelv associated with Aschcrsoiiia alcyrodis of Webber, and suggests 
the possibility of one being a form of the other. In regard to this point he 
writes : 

Intermingled witli the brightly colored Aschersonia stromata on the leaf of 
flciiiiiigia sfrobilifcra were other brown ones. Many of these latter were evidently 
old or arrested Aschersonia stromata, as sections of them revealed closed pycnidia. 
Others again were flatter, more nearly resembling Web1)er's brown fungus, thus sug- 
gesting the possibility of all these sterile pustules being really connected with Ascher- 
sonia. The two fungi often appear in association on the same scale and even on the 
same leaf. Webber mentions that A. alcyrodis was present on those orange bushes 
containing also the "brown mealy wing fungus". In the Ceylon specimen on Meme- 
cylon the two were intimately associated. Atmospheric conditions such as dryness 
may also influence the development of the Aschersonia as to induce it to assume a 
sterile resting form. This, when conditions are again favorable, might send out in- 
fecting hyphae over the leaf surface. Webber's accou;it of how this brown fungus 
develops and spreads hardly favors such a view. However, its close association with 
Aschersonia is a point to be kept in mind. By cultures perhaps this sterile form might 
be induced to form some fructifications, and so a clue to its nature and relationship 
might be obtained. 

The cultures of Aschcrsoiiio alcyrodis and Aschersonia flavo-citriiia made 
by the author on various media and at different times of year with varying 
amounts of water, never showed any tendency to develop the brown sterile 
form of the Brown fungus. In Florida there seems to be no evidence to 
indicate any connection between this sterile Brown fungus and the Ascher- 
sonias parasitic upon Alcyrodcs citri. 

METHODS OF INTRODUCTION. 

\\'ebber, in the bulletin previously referred to. describes in some detail 
the method of introducing this fungus into trees infested with Alcyrodcs 
citri by pinning in leaves, or by planting young fungus-bearing trees in 
such a way that their leaves would come in contact with the larvae-bearing 
leaves to be infected with fungus. E. W. Berger''-* has recently produced 
some infection by grinding up the brown stromata, stirring with water, and 
spraying this water upon infested leaves. 

A number of attempts have been made by the writer to grow cultures of 
this fungus in the laboratory, but so far he has been unsuccessful. In one 
case where stromata of the brown fungus were placed close to a drop of 
agar in a hanging drop culture, short tortuous hyphae were seen to grow 



Annals Roy. Bot. Gard. Peradeniya, Vol. Ill, Part I, p. 52, 1906. 
Fla. E.xp. Sta. Bui. 88, p. 64, 1906. 



36 FUNGI PARASITIC UPON ALEYRODKS CITRI. 

out from the edge. This is the only growth that has so far been observed 
under artificial conditions. 

DISTRIBUTION OF THE BROWN FUNGUS. 

Florida. — Alva, Bartow, Buckingham, Bradentown, Fort Myers, Largo, 
Leesburg, Manatee, Oneco, Orlando, Palmetto, St. Augustine and St. 
Petersburg, on Aleyrodes citri. 

Ceylon, as reported by J. Parkin, on various species of Aleyrodes. 

SUPPLEMENTARY NOTES. 

1. Since the above has been written, what appear to be the spores of 
the Broivn fungus of Aleyrodes citri have been discovered. These spores 
are germinating in hanging drop cultures of sugar solutions, and are pro- 
ducing hyphae that seem to be identical with those of the Brown fungus. 
Further study is needed to prove the relationship of these spores to the 
Brown fungus. 

2. A species of Sporotrichiim has been discovered upon the adult and 
larva of Aleyrodes citri. This fungus seems to be responsible, during damp 
weather, for the premature death of great numbers of adults. Cultures and 
inoculation experiments are being carried on, the results of which will be 
published later. 

3. Since the writing of this thesis it has been shown by Dr. E. W. Berger, 
Entomologist of the Florida Experiment Station, that the insects hitherto 
designated as Aleyrodes citri comprise two distinct species of Aleyrodes; 
one with smooth eggs and clear wings, and the other with rough eggs 
covered with a delicate net of five- and six-sided meshes, and wings with 
a smoky-colored area at the end of each fore wing. Specific differences 
have also been observed in the first and fourth stage larvae. (See Press 
Bulletin 97, Fla. Agri. Exp. Sta., and Proc. Fla. Sta. Hort. Soc, p. 86, 1908.) 
Dr. Berger's observations and also those of the writer seem to show that 
these two species of Aleyrodes are differently attacked by the Aschersonias 
(A. alcyrodis and A. flaz'o-citrina) , and also by the Brown fungus and 
Microccra sp. Aschcrsonia flai o-citriiia attacks readily only the smoky- 
winged Aleyrodes, but will attack the clear-winged species. Aschcrsonia 
alcyrodis and the Brown fungus attack both species of Aleyrodes in an equal 
degree, but the greater number of the specimens so far observed have been 
found upon the clear-winged species. The Microccra has been found on 
both species of Aleyrodes, although it is more efifective upon the smoky- 
winged species. The infection experiments described in the foregoing pages 
with cultures of Microccra sp. (page 32) and VcrticilUum hetcrocladum 
(page 2-1:) were made upon the clear- winged species. The infection ex- 
periments also made by E. W. Berger at St. Petersburg and Gainesville 
(page 16) were also upon the clear-winged Aleyrodes. 

October 1, 1908. 



SUMMARY. 37 

SUMMARY. 

1. Entomogenous species of fungi representing many different genera 
have been described in the past hundred or more years. 

2. These have not. until recent times, been studied from an economic 
standpoint. The greatest success in the use of fungi to combat insect 
pests seems to have been attained in Florida, where proper conditions of 
temperature and moisture are present. 

3. Alcyrodcs cifri R. & H., known since 1885 as a pest to citrus trees in 
Florida, has spread to many citrus districts since that time, doing much 
damage chiefly by creating conditions favorable to the growth of Meliola. 

4. A studv of the fungi parasitic upon Aleyrodcs citri shows that there 
are at least six species, five of which have been grown upon culture media 
in the laboratory. 

."). Asclicrsoiiia alcyrodis Webber is the most widely distributed fungus 
parasite of Alcyrodcs cifri. It is easily isolated and grown in pure cultures 
in 5 to 10 per cent, glucose agar medium, maturing a stroma in 30 to 40 
days. 

6. Healthv larvae of Alcyrodcs citri may be infected from cultures of 
this fungus b}- spraying a mixture of conidia in water on trees infested with 
Alcyrodcs citri. 

T. Aschcrsojiia fhvvo-citrina P. Henn., which was recently found in 
eastern Florida, is also an important parasite of Alcyrodcs citri. Its growth 
on culture media is the same as that of A. alc\rodis. 

8. Conidia of both of the Aschersonias germinated best in a 5 to 10 per 
cent, solution of glucose in water. Percentages of sugar above or below 
this retarded germination. Conidia from stromata dried in the laboratory 
for more than 28 days failed to germinate. 

\). J'crficilliiiiii hefcrocladum Penz. has been recently shown to occur 
parasitically upon Alcyrodcs citri. It has also been observed on a number 
of other insects. Cultures and inoculation experiments show that this 
fungus is distinct from the "Brown fungus", which it somewhat resembles in 
general appearance, and with which it is frequently found associated. 

10. The growth of this fungus in cultures is nnich more rapid than that 
of the two species of Aschersonia described. 

11. Sphacrostilbc coccophUa, known since 1848, is W'Orld-W'ide in dis- 
tribution, and has been reported on no less than fifteen species of scale 
insects, in addition to being found on Alcyrodcs citri. 

12. Sphacrostilbc coccopliila has been used in Florida as an effective 
parasite in controlling the San Jose scale and other scale insects. In more 
northern States it has not proved to be effective. It is possibly a w^eak 
parasite of Alcyrodcs citri. 

13. Microccra sp., recently discovered, has been found in a number of 
places in Florida attacking larvae of Alcyrodcs citri. Abundant cultures of 



38 FUNCI I'ARASITJC UPON ALIiVRODES CITRI. 

this fungus may he grown in a few clays, and larvae of Alcyrodcs citri may 
be infected from these cultures. Conidia of this fungus varv greath' in size 
under different conditions of growth. 

14. The Brown fungus, known in Florida since ISDG, has never been 
observed to produce spores and is therefore unclassified. Its growth and 
development on Alcyrodcs citri were described by Webber. All attempts to 
grow this fungus in pure cultures have failed. ( See, however. Supplement- 
ary Note 1.) 

BIBLIOGRAPHY. 

The literature referred to in this bibliography is grouped under seven heads, corre- 
sponding to the seven divisions under which the subject is discussed. The references 
in each division arc arranged in chronological order. All Init three of the papers 
have been seen Iw the author. These three are designated In- an (*) asterisk. 

Gf:NEKAl, LITERATURE. 

("88) Forbes, S. A. On our present knowledge concerning Insect Diseases. Psvche, 
Vol. V, pp. 3-12, 1888-90. ( Bil)liography, pp. 1,5-22.) 

('88) Thaxter, Roland. Tlie Entomophthoraceae of the United States. Memoirs 
of the Boston Soc. of Nat. History, Vol. IV, No. 6, 1S8S. (With bibHography.) 

('88) Lugger, Otto. Fungi Which Kill Insects. L'niv. of Minn. Ann. Rept. Agr., 
pp. 380-392, 1888. 

('92) Cooke, M. C. Vegetable Wasps and Plant Worms, London, 1892. 

('93) Riley, C. V. and Howard, L- O. Insect Life, Div. of Ento., Wash., D. C, 
Vol. V, No. 4, p. 220, 1893. 

('95) Pettit, R. H. Studies in Artificial Cultures of Entomogenous Fungi. Cor- 
nell Univ. Agr. Exp. Sta. Bui. 97, 1895 (with bibliography). 

('95) Forbes, S. A. Experiments With the Mu.scadine Disease of the Chinch- 
bug, etc. 111. Agr. Exp. Sta. Bui. 38, 1895. 

('97) Rolfs, P. H. A Disease of the San Jose Scale. Fla. .Agr. Exp. Sta. Bui. 41, 
1897. 

('98) Forbes, S. A. 111. Agr. Exp. Sta. Bui. 56. pp. 270-280, 1S98. 

('06) Parkin, J. Fungi Parasitic Upon Scale Insects (Coccidae and Aleyrodidae), 
etc. Ann. Roy. Rot. Gardens Peradeniya, Vol. HI, Part I. (With bibliography.) 

ASCHERSONIA AI.EYRODIS WEBBER. 

('94) Webber, H. J. Preliminary Notice of a Fungus Parasite on Alevrodes 
citri. Journ. of Mycol., Vol. VII, No.'4, p. 363, 1894. 

('96) Webber, H. J. Proc. Fla. State Hort. Soc, p. 73, 1896. 

('96) Webber, H. J. The Principal Diseases of Citrus Fruits in Florida. Div. 
of Veg. Phys. and Path.. Bui. 8, Washington, D. C, p. 27, 1896. 

('97) Webber, H. J. Sooty Mold of the Orange. Div. of Veg. Ph\s. and Path.. 
Bui. 13, p. 20, Washington, D. C, 1897. 

('99) Saccardo, P. A. Sylloge Fungorum, XIV. p. 991, 1899. 

('00) Hume, H. H. Some Citrus Troubles. Fla. .\gr. Exp. Sta. Bui. 53, p. 164, 
1900. 

('03) Gossard, H. A. Fla. Agr. Exp. Sta. Bui. 67. pp. 622-621!. 1903. 

('04) Hume, H. H. Citrus Fruits and Their Culture, pp. 547-550, Jacksonville, 
Florida, 1904. 

('05) Sellards, E. H. Fla. Agr. Exp. Sta. Rept.. pp. 26-27. 1905. 

('06) Earle, F. S. Primer Informe Anual de la Estacion Central Agronomica de 
Cuba, 1904-1905, p. 169, 1906. 

('06) Parkin, J. Fungi Parasitic Upon Scale Insects. Annals of Roval Bot. Card. 
Peradeniya, Vol. Ill, Part I. p. 36, 1906. 

('06) Berger, E. W. Fla. Agr. Exp. Sta. Rept.. p. xix. 1906. 

('07) Berger, E. W. Fla. Agr. Exp. Sta. Bui. 88, pp. 54-65, 1907. 

('07) Berger, E. W. Fla. Agr. Exp. Sta. Rept., p. xxxi, 1907. 

("07) Fawcett, H. S. Fla. Agr. Exp. Sta. Rept., p. xlviii, 1907. 



HIBLIOGRAPHY. 39 

('07) Kirkaldy, G. W. and Kotinsky, J. Board of Commissioners of Agr. and 
Forestry, Div. of Entomology, Hawaiian Sugar Planters' Exp. Sta., Bui. 2, pp. 57 and 
60, 1907. 

("08) Berger, E. W. Fla. Agr. Exp. Sta. Press Bui. SO, ]<)0S. 

('08) Cook, ]\1. T. and Home, W. T. Insects and Diseases of Orange. Cuba 
Agr. Exp. Sta. Bui. 9, p. 31. 1908. 

('OS) Rolfs, P. H. and Fawcett, H. S. Fungus Diseases of Scale Insects and 
Whitefly. Fla. Agr. Exp. Sta. Bui. 94. 1908. 

ASCHERSONIA FLAVG-CITRINA P. HENN. 

('02) Hennings, P. Hedwigia, Vol. 41, p. :)07. 1902. 

('04) Hennings. Festschrift ftir P. Ascherson, p. G8, 1904. 

('06) Saccardo. Svlloge Fungorum, xviii, p. 413, 1906. 

('07) Rolfs, P. H." Fla. Agr. Exp. Sta. Rept., p. 16, 1907. 

('07) Berger, E. W. Fla. Agr. Exp. Sta. Rept., pp. 31, 34 and 35, 1907. 

('07) Berger, E. W. Whitefly Conditions in 1906. Fla. Agr. Exp. Sta. Bui. 88. 
1907. 

("07) Berger. E. W. Control of Whitefly l)y Natural Means. Fla. State Hort. 
Soc. Rept.. pp. 73-78. 1907. 

('07) Fawcett, H. S. Fla. Agr. Exp. Sta. Rept.. p. xlvii. 1907. 

('08) Rolfs. P. H. and Fawcett. H. S. Fla. Agr. Exp. Sta. Bui. 94. 1908. 

VERTICir.LIUM HETEROCLADITM PENZ. 

('82) Penzig, O. Flora Italica, t. 1193, Mich. U, p. 462. 1882.* 

C86) Saccardo. Sylloge Fungorum, IV, p. 151, 1886. 

('87) Penzig, O. Studi Botanici sugli Agrumi e sulle Plante Affini. p. :;98, 
Tavola xli. Fig. 3. Roma, 1887. 

('04) Gueguen. Les Champignons parasites de rhomine et des animaux. p. 252, 
Paris. 1904.* 

("06) Parkin. J. Ann. Roy. Bot. Gard. Peradeniya. Vol. III. Part I. p. 45, 1906. 

( '07 ) Fawcett, H. S. The Cinnamon Fungus of the Whitefly. Fla. Agr. Exp. 
Sta. Press Bulletin 76, 1907. 

SPHAEROSTILBE COCCOPHIEA TUE. 

('48) Desmazieres. Ann. des Sc. Nat., Tome x, p. 359, 1848. 

('65) Tulasne. Carpologia. Vol. Ill, p. 105, 1865.* 

('83) Saccardo. Sylloge Fungorum, II, p. 513. 1883. 

('92) Cooke. M. C. Vegetable Wasps and Plant Worms, p. 322, Plate 2, Fig. 22, 
London, 1892. 

("92) Cockerell, T. D. A. Bui. Bot. Dept. Jamaica. No. 36. p. 6, 1892. 

("92) Ellis and E'verhart. North American Pyrenomycetes, p. Ill, 1892. 

("94) Trvon, H. Queensland Dept. of Agr.. Bui. 4, 'p. 15, 1894. 

("96) Rolfs, P. H. Fla. Agr. Exp. Sta. Rept.. p. 49, 1896. 

('97) Rolfs. P. H. A Disease of the San Jose Scale. Fla. Agr. Exp. Sta. Bui. 41, 
1897. 

("97) Craig. J. Canadian Exp. Farm Rept. 119, 1897. 

('97) Smith. J. B. New Jersey Agr. Exp. Sta. Rept. 18, pp. 470-479, 1897. 

("98) Smith. J. B. New Jersey Exp. Sta. Rept. 19. pp. 445-446. 1898. 

("98) Rolfs, P. H. Fla. Agr. Exp. Sta. Rept.. p. 7. 1898. 

("98) Forbes, S. A. 111. Agr. Exp. Sta. Bui. 56. pp. .270-280, 1898. 

("98) Webster, F. M. Ohio Agr. Exp. Sta. Bui. 103, p. 198. 1898. 

('99) McAlpine. D. Fungus Diseases of Citrus Trees in Australia. Dept. of .-\gr. 
Queensland, p. 113. Figs. 181-182. pp. 27 and 28, 1899. 

Coo) Rolfs, P. H. Proc. Fla. State Hort. Soc, p. 65. 19()(), 

Coo) Earle. F. S. Ala. Agr. Exp. Sta. Bui. 106. p. 175. 1900. 

("00) Gossard. H. A. Fla. Agr. Exp. Sta. Rept. 1899-1900, p. 55. 1900. 

("00) Gossard. H. A. Fla. Agr. Exp. Sta. Bui. 51, p. 125. 1900. 

roi) Fuller. First Rept. of Gov. Entomologist. Dept. of Agr.. Natal, p. 99. 1901. 

Col) Gossard, H. A. Fla. Agr. Exp. Sta. Rept., p. 63. 1901. 

("02) Gossard, H. A. Fla. Agr. Exp. Sta. Bui. 61, pp. 479, 487-491. 1902. 

("03) Gossard. H. A. Fla. Agr. Exp. Sta. Bui. 67. p. 623, 1903. 

('03) Earle. F. S. Ann. Rept. Off. of Exp. Sta.. p. 457, Washington. D. C. 1903. 

('03) Smith, T. B. New Jersey Exp. Sta. Rept. 24, p. 567, 1903. 

('04) Rolfs. P. H. Proc. Fla. State Hort. Soc, p. 63. 1904. 

('04) Hume. H. H. Citrus Fruits and Their Culture, p. 548. Jacksonyille, Flor- 
ida. 1904. 



40 FUNGI PARASITIC UPON ALEYRODES ClTRI. 

("04) Kuwana, S. I. Japan Imp. Agr. Exp. Sta. Rept., p. 26, lOO-t. 

C'05) Sellards, E. H. Fla. Agr. Exp. Sta. Rept., p 27, 1905. 

('06) E'arle, F. S. Primer Informe Anual de la Estacion Central Agronomica 
de Cuba, 1904-1905, p. 162, 1906. 

('06) Parkin, J. Ann. Roy. Bot. Card. Peradeniya. Vol. Ill, Part I. p. 4S-49, 1906. 

('07) Berger, E. W. Fla. Agr. Exp. Sta. Rept., pp. 31, 36, 37. 1907. 

('07) Berger, E. W. Proc. Fla. State Hort. Soc, p. 71, 1907. 

('07) Berger, E. W. Whiteily Conditions in 1906. Fla. Agr. Exp. Sta. Bui. SS, 
p. 54, 1907. 

('07) Griffing. Fla. State Hort. Soc. Kept., pp. 54-55, 1907. 

('08) Cook, M. T. and Home, W. T. Insects and Orange Diseases. Cuba Exp. 
Sta. Bui. 9, p. 22, February, 1908. 

('08) Howard, C. W. The Scale Insects of Citrus Trees. Dept. of Agr., Trans- 
vaal. Reprint from Transvaal Agr. Jour. No. 148, p. 6, 1908. 

('08) Rolfs, P. H. and Fawcett, H. S. Fungus Diseases of Scale Insects and 
Whitefly. Fla. Agr. Exp. Sta. Bui. 94, 1908. 

MICROCERA SP. 

('07) Fawcett, H. S. A New Whiteflv Fungus. Fla. Agr. Exp. Sta. Press Bui. 
No. 68, 1907. 

Webber's brown eungus. 

('96) Webber, H. J. Proc. Fla. State Hort. Soc, p. 74, 1896. 

('97) Webber, H. J. Proc. Fla. State Hort. Soc, pp. 55-56. 1897. 

('97) Webber, H. J. Sooty Mold of the Orange Div. of Veg. Phvs. and Path., 
Washington, D. C, Bui. 13, pp. 27-30, 1897. 

Coo) Pettigrew, A. J. Proc Fla. State Hort. Soc, p. 63, 1900. 

('00) Hume, H. H. Fla. Agr. Exp. Sta. Bui. 53, p. 164, 1900. 

('03) Gossard, H. A. Fla. Agr. Exp. Sta. Bui. 67, pp. 621-622, 1903. 

('04) Hume, H. H. Citrus Fruits and Their Culture, p. 550, Jacksonville, Flor- 
ida. 1904. 

('05) Sellards, E. H. Fla. Agr. Exp. Sta. Rept., p. 26, 1905. 

('06) Parkin, J. Fungi Parasitic Upon Scale Insects. Annals of Rov. Bot. Card. 
Peradeniya. Vol. III. Part I. p. 52, 1906. 

('06) Berger, E. W. Fla. Agr. Exp. Sta. Rept., p. xix, 1906. 

('07) Berger, E. W. Fla. Agr. Exp. Sta. Bui. 88, pp. 64-65. 1907. 

('07) Berger, E. W. Fla. Agr. Exp. Sta. Rept, p. xxxi, 1907. 

('OS) Rolfs, P. H. and Fawcett, H. S. Fungus Diseases of Scale Insects and 
Whitefly. Fla. Agr. Exp. Sta. Bui. 94, 1908. 

^ , EXPLANATION OF PLATES. 

Pl.vte I. 

Fig. 20. — Aschersonia alcyrodis. Culture in petri dish of 5 per cent, glucose agar 
poured December 7, 1906 ; showing mature stroma 36 days old. The central 
raised portion was red, and contained the pycnidial cavities with spores. 

Fig. 21. — Aschersonia aleyrodis. Culture on rice after 5 weeks, grown at room 
temperature. 

Fig. 22. — Aschersonia alcyrodis. Culture on sweet potato plug, after 5 weeks. 
Grown in refrigerator after first few days. 

Fig. 23. — Aschersonia alcyrodis. Culture on white corn meal after 5 weeks. Grown 
at room temperature. 

Pl.\te II. 

Fig. 24. — Aschersonia flavo-citrina. Citrus leaf showing stromata of the fungus 
in the position originally assumed by larvae of Alcyrodes citri. The hemi- 
spherical raised center was yellow with a fringe of outgrowing hyphae. 

Fig. 25. — Aschersonia aleyrodis. Citrus leaf showing stromata. The raised center 
was red instead of yellow, as in the previous figure. 

Plate III. 

Fig. 26. — Aschersonia flavo-citrina. Culture on petri dish of 5 per cent, glucose 

agar made -|-0.5 to phenolphthalein, after 33 days. Culture poured September 

14, 1906; showing the mature stromata one and a half times natural size. 
Fig. 27. — Aschersonia flavo-citrina. Culture on petri dish of 5 to 10 per cent. 

glucose agar, after 40 days, showing how stromata will spread when given 

room to grow. 



KXPI^ANATION OF PLATKS. 41 

Plate IV. 

Figs. 28-30. — Asclicrsoiiia flavo-citrina. Cultures on sweet potato plugs, inoculated 

November 1, 1906, after 60 days. 
Fig. 31. — J'crticilliiiin hctcrocladuin. Citrus leaf shcnving fungus pustules on 
larvae of Alcyvodcs citri. 

Plate V. 

Fig 32. — I'crlicilliuiu lu'tcrniladiini. Culture in test-tube on bread. 

Fig. 33. — ]\-vticUliitm lirtcrocladiiiii. Culture in test-tube on Irish potato plug. 

Fig. 34. — J'crticillium hctcrocladum. Culture on glucose agar, showing brown 

pustules. 

Fig. 35. — J'crtici/liuiii liclcrocladiDii. Leaf of privet bearing larvae of Alcyrodcs 

atri infected witli the fungus by means of a citrus leaf containing pustules. 

Plate VI. 

Fig. 36. — Sphacrostilbc cuccophila. Sporodochia of the fungus on bodies of 

Aspidiotus hcderac, on Chinaberry twig. 
Fig. 37. — Sphacrostilbc coccopliila. Sporodochia of fungus on bodies of MytHaspis 

cifricola on citrus twig. 
Fig. 38. — Sphacrostilbc coccopliila. Perithecia of fungus on Myfilaspis cifricola 

on bark of citrus. Twice natural size. 
Fig. 39 and 40. — Microccra sp. Cultures on rice showing loose fluffy growtii on 

top of medium. Natural size. 
Fig. 41. — Microccra sp. Citrus leaf with larvae of Alcyrodcs citri infected with 

the fungus. The fungus is shown by white fringes on the edges of a number 

of the larvae. 

Plate VII. 

Fig. 42. — The Brown Fungus of Webber. Citrus leaf with brown pustules that 

have formed on larvae of Alcyrodcs citri. (Photographed by H. H. Hume.) 
Fig. 43. — Cladosporiuin sp. A super-parasite found growing over Asclicrsoiiia 

flavo-citrina on leaf of citrus. 



Plate I 




T'v^fi. 20-23. ('iiltnrt'H of Aschersonia aleyrodis. 



Plate II 




Fig. *J-1. Aschersonia flavo-citrina (Hi citrus leaf. 



^^^■i 


\ 


k. 


^^^^^^^^^^^^^^^H^^^^^E*^-. 










HF 


^^^^^^^^^^^^^^^^^^^■^■('''VB^HK^'r'' -<^-^ ''^fj^^^^^KB^ 




^ 



Fig. 25. Aschersonia aleyrodis on citrus leaf. 



Plate III 




Fig. JG. Cultures of Aschersonia flavo-citrina. 



Plate I [I — Continued 




Fig'. 27. Cultures of Aschersonia flavo-citrina. 



Plate IV 





Fiofs. '28 -oO. Cultures (^i Aschersonia flavo-citrina. 




Fig. ;>1. Verticillium heterocladum on citrus leaf. 



Plate V 




f^ 



3Z 




5-Ti;«5«s»3 




34- 




Fi^^s. 32-34. Culturei^ oi Verticillium heterocladutn. 
Fig. 3o. Verticillium heterocladum on Aleyrodes citri on privet leaf. 



Plate VI 





Figs. 36-37. Sporodochia of Sphaerostilbe coccophila. 

Fig. 38. Perithecia of Sphaerostilbe coccophila. 

Figs. 39-40. Cultures of Microcera sp. 

Fig. 41. Microcera sp. on Aleyrodes citri on citrus leaf. 



Plate VII 








Fiji;. 42. Brown fungus on Aleyrodes citri. 








^"^-*— »-iti^ 'Ys^^ 



Fig. 43. A super-parasite (Cladosporiuin sp.) upon Aschersonia flavo-citrina. 



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